diff --git a/Doc/c-api/init_config.rst b/Doc/c-api/init_config.rst
index 4c77d5d1e0e..15b8b94d5a7 100644
--- a/Doc/c-api/init_config.rst
+++ b/Doc/c-api/init_config.rst
@@ -194,25 +194,18 @@ PyPreConfig
    * Configure the LC_CTYPE locale
    * Set the UTF-8 mode
 
-   The :c:member:`struct_size` field must be explicitly initialized to
-   ``sizeof(PyPreConfig)``.
-
    Function to initialize a preconfiguration:
 
-   .. c:function:: PyStatus PyPreConfig_InitIsolatedConfig(PyPreConfig *preconfig)
+   .. c:function:: void PyPreConfig_InitIsolatedConfig(PyPreConfig *preconfig)
 
       Initialize the preconfiguration with :ref:`Python Configuration
       <init-python-config>`.
 
-   .. c:function:: PyStatus PyPreConfig_InitPythonConfig(PyPreConfig *preconfig)
+   .. c:function:: void PyPreConfig_InitPythonConfig(PyPreConfig *preconfig)
 
       Initialize the preconfiguration with :ref:`Isolated Configuration
       <init-isolated-conf>`.
 
-   The caller of these functions is responsible to handle exceptions (error or
-   exit) using :c:func:`PyStatus_Exception` and
-   :c:func:`Py_ExitStatusException`.
-
    Structure fields:
 
    .. c:member:: int allocator
@@ -274,13 +267,6 @@ PyPreConfig
       same way the regular Python parses command line arguments: see
       :ref:`Command Line Arguments <using-on-cmdline>`.
 
-   .. c:member:: size_t struct_size
-
-      Size of the structure in bytes: must be initialized to
-      ``sizeof(PyPreConfig)``.
-
-      Field used for API and ABI compatibility.
-
    .. c:member:: int use_environment
 
       See :c:member:`PyConfig.use_environment`.
@@ -332,12 +318,7 @@ Example using the preinitialization to enable the UTF-8 Mode::
 
     PyStatus status;
     PyPreConfig preconfig;
-    preconfig.struct_size = sizeof(PyPreConfig);
-
-    status = PyPreConfig_InitPythonConfig(&preconfig);
-    if (PyStatus_Exception(status)) {
-        Py_ExitStatusException(status);
-    }
+    PyPreConfig_InitPythonConfig(&preconfig);
 
     preconfig.utf8_mode = 1;
 
@@ -360,9 +341,6 @@ PyConfig
 
    Structure containing most parameters to configure Python.
 
-   The :c:member:`struct_size` field must be explicitly initialized to
-   ``sizeof(PyConfig)``.
-
    Structure methods:
 
    .. c:function:: PyStatus PyConfig_InitPythonConfig(PyConfig *config)
@@ -679,13 +657,6 @@ PyConfig
       Encoding and encoding errors of :data:`sys.stdin`, :data:`sys.stdout` and
       :data:`sys.stderr`.
 
-   .. c:member:: size_t struct_size
-
-      Size of the structure in bytes: must be initialized to
-      ``sizeof(PyConfig)``.
-
-      Field used for API and ABI compatibility.
-
    .. c:member:: int tracemalloc
 
       If non-zero, call :func:`tracemalloc.start` at startup.
@@ -754,7 +725,6 @@ Example setting the program name::
     {
         PyStatus status;
         PyConfig config;
-        config.struct_size = sizeof(PyConfig);
 
         status = PyConfig_InitPythonConfig(&config);
         if (PyStatus_Exception(status)) {
@@ -787,7 +757,6 @@ configuration, and then override some parameters::
     {
         PyStatus status;
         PyConfig config;
-        config.struct_size = sizeof(PyConfig);
 
         status = PyConfig_InitPythonConfig(&config);
         if (PyStatus_Exception(status)) {
@@ -875,7 +844,6 @@ Example of customized Python always running in isolated mode::
     {
         PyStatus status;
         PyConfig config;
-        config.struct_size = sizeof(PyConfig);
 
         status = PyConfig_InitPythonConfig(&config);
         if (PyStatus_Exception(status)) {
@@ -1067,7 +1035,6 @@ phases::
     {
         PyStatus status;
         PyConfig config;
-        config.struct_size = sizeof(PyConfig);
 
         status = PyConfig_InitPythonConfig(&config);
         if (PyStatus_Exception(status)) {
diff --git a/Include/cpython/initconfig.h b/Include/cpython/initconfig.h
index 8ce5622c5c4..25e02cea10d 100644
--- a/Include/cpython/initconfig.h
+++ b/Include/cpython/initconfig.h
@@ -45,10 +45,6 @@ PyAPI_FUNC(PyStatus) PyWideStringList_Insert(PyWideStringList *list,
 /* --- PyPreConfig ----------------------------------------------- */
 
 typedef struct {
-    /* Size of the structure in bytes: must be initialized to
-       sizeof(PyPreConfig). Field used for API and ABI compatibility. */
-    size_t struct_size;
-
     int _config_init;     /* _PyConfigInitEnum value */
 
     /* Parse Py_PreInitializeFromBytesArgs() arguments?
@@ -124,17 +120,13 @@ typedef struct {
     int allocator;
 } PyPreConfig;
 
-PyAPI_FUNC(PyStatus) PyPreConfig_InitPythonConfig(PyPreConfig *config);
-PyAPI_FUNC(PyStatus) PyPreConfig_InitIsolatedConfig(PyPreConfig *config);
+PyAPI_FUNC(void) PyPreConfig_InitPythonConfig(PyPreConfig *config);
+PyAPI_FUNC(void) PyPreConfig_InitIsolatedConfig(PyPreConfig *config);
 
 
 /* --- PyConfig ---------------------------------------------- */
 
 typedef struct {
-    /* Size of the structure in bytes: must be initialized to
-       sizeof(PyConfig). Field used for API and ABI compatibility. */
-    size_t struct_size;
-
     int _config_init;     /* _PyConfigInitEnum value */
 
     int isolated;         /* Isolated mode? see PyPreConfig.isolated */
diff --git a/Include/internal/pycore_initconfig.h b/Include/internal/pycore_initconfig.h
index eb6490f5a87..e9810bcf90a 100644
--- a/Include/internal/pycore_initconfig.h
+++ b/Include/internal/pycore_initconfig.h
@@ -120,8 +120,8 @@ extern PyStatus _PyPreCmdline_Read(_PyPreCmdline *cmdline,
 
 /* --- PyPreConfig ----------------------------------------------- */
 
-PyAPI_FUNC(PyStatus) _PyPreConfig_InitCompatConfig(PyPreConfig *preconfig);
-extern PyStatus _PyPreConfig_InitFromConfig(
+PyAPI_FUNC(void) _PyPreConfig_InitCompatConfig(PyPreConfig *preconfig);
+extern void _PyPreConfig_InitFromConfig(
     PyPreConfig *preconfig,
     const PyConfig *config);
 extern PyStatus _PyPreConfig_InitFromPreConfig(
diff --git a/Misc/NEWS.d/next/C API/2019-09-28-03-43-27.bpo-38304.RqHAwd.rst b/Misc/NEWS.d/next/C API/2019-09-28-03-43-27.bpo-38304.RqHAwd.rst
deleted file mode 100644
index b797933d05d..00000000000
--- a/Misc/NEWS.d/next/C API/2019-09-28-03-43-27.bpo-38304.RqHAwd.rst	
+++ /dev/null
@@ -1,3 +0,0 @@
-Add a new ``struct_size`` field to :c:type:`PyPreConfig` and :c:type:`PyConfig`
-structures to allow to modify these structures in the future without breaking
-the backward compatibility.
diff --git a/Modules/main.c b/Modules/main.c
index ef6c66a8dbe..9cbf3ac7060 100644
--- a/Modules/main.c
+++ b/Modules/main.c
@@ -53,12 +53,7 @@ pymain_init(const _PyArgv *args)
 #endif
 
     PyPreConfig preconfig;
-    preconfig.struct_size = sizeof(PyPreConfig);
-
-    status = PyPreConfig_InitPythonConfig(&preconfig);
-    if (_PyStatus_EXCEPTION(status)) {
-        return status;
-    }
+    PyPreConfig_InitPythonConfig(&preconfig);
 
     status = _Py_PreInitializeFromPyArgv(&preconfig, args);
     if (_PyStatus_EXCEPTION(status)) {
@@ -66,7 +61,7 @@ pymain_init(const _PyArgv *args)
     }
 
     PyConfig config;
-    config.struct_size = sizeof(PyConfig);
+
     status = PyConfig_InitPythonConfig(&config);
     if (_PyStatus_EXCEPTION(status)) {
         goto done;
diff --git a/PC/python_uwp.cpp b/PC/python_uwp.cpp
index 2656d188c25..758c8f73725 100644
--- a/PC/python_uwp.cpp
+++ b/PC/python_uwp.cpp
@@ -165,12 +165,8 @@ int
 wmain(int argc, wchar_t **argv)
 {
     PyStatus status;
-
     PyPreConfig preconfig;
-    preconfig.struct_size = sizeof(PyPreConfig);
-
     PyConfig config;
-    config.struct_size = sizeof(PyConfig);
 
     const wchar_t *moduleName = NULL;
     const wchar_t *p = wcsrchr(argv[0], L'\\');
@@ -189,10 +185,7 @@ wmain(int argc, wchar_t **argv)
         }
     }
 
-    status = PyPreConfig_InitPythonConfig(&preconfig);
-    if (PyStatus_Exception(status)) {
-        goto fail_without_config;
-    }
+    PyPreConfig_InitPythonConfig(&preconfig);
     if (!moduleName) {
         status = Py_PreInitializeFromArgs(&preconfig, argc, argv);
         if (PyStatus_Exception(status)) {
diff --git a/Programs/_freeze_importlib.c b/Programs/_freeze_importlib.c
index 7c494c2786c..74735f279c5 100644
--- a/Programs/_freeze_importlib.c
+++ b/Programs/_freeze_importlib.c
@@ -78,7 +78,6 @@ main(int argc, char *argv[])
 
     PyStatus status;
     PyConfig config;
-    config.struct_size = sizeof(PyConfig);
 
     status = PyConfig_InitIsolatedConfig(&config);
     if (PyStatus_Exception(status)) {
diff --git a/Programs/_testembed.c b/Programs/_testembed.c
index c8600d58f0b..d2d4c7f8c65 100644
--- a/Programs/_testembed.c
+++ b/Programs/_testembed.c
@@ -385,12 +385,7 @@ static int check_init_compat_config(int preinit)
 
     if (preinit) {
         PyPreConfig preconfig;
-        preconfig.struct_size = sizeof(PyPreConfig);
-
-        status = _PyPreConfig_InitCompatConfig(&preconfig);
-        if (PyStatus_Exception(status)) {
-            Py_ExitStatusException(status);
-        }
+        _PyPreConfig_InitCompatConfig(&preconfig);
 
         status = Py_PreInitialize(&preconfig);
         if (PyStatus_Exception(status)) {
@@ -399,7 +394,6 @@ static int check_init_compat_config(int preinit)
     }
 
     PyConfig config;
-    config.struct_size = sizeof(PyConfig);
 
     status = _PyConfig_InitCompatConfig(&config);
     if (PyStatus_Exception(status)) {
@@ -478,15 +472,8 @@ static int test_init_global_config(void)
 
 static int test_init_from_config(void)
 {
-    PyStatus status;
-
     PyPreConfig preconfig;
-    preconfig.struct_size = sizeof(PyPreConfig);
-
-    status = _PyPreConfig_InitCompatConfig(&preconfig);
-    if (PyStatus_Exception(status)) {
-        Py_ExitStatusException(status);
-    }
+    _PyPreConfig_InitCompatConfig(&preconfig);
 
     putenv("PYTHONMALLOC=malloc_debug");
     preconfig.allocator = PYMEM_ALLOCATOR_MALLOC;
@@ -495,13 +482,12 @@ static int test_init_from_config(void)
     Py_UTF8Mode = 0;
     preconfig.utf8_mode = 1;
 
-    status = Py_PreInitialize(&preconfig);
+    PyStatus status = Py_PreInitialize(&preconfig);
     if (PyStatus_Exception(status)) {
         Py_ExitStatusException(status);
     }
 
     PyConfig config;
-    config.struct_size = sizeof(PyConfig);
 
     status = _PyConfig_InitCompatConfig(&config);
     if (PyStatus_Exception(status)) {
@@ -638,7 +624,6 @@ static int check_init_parse_argv(int parse_argv)
     PyStatus status;
 
     PyConfig config;
-    config.struct_size = sizeof(PyConfig);
 
     status = PyConfig_InitPythonConfig(&config);
     if (PyStatus_Exception(status)) {
@@ -725,7 +710,6 @@ static int test_init_python_env(void)
     set_all_env_vars();
 
     PyConfig config;
-    config.struct_size = sizeof(PyConfig);
 
     status = PyConfig_InitPythonConfig(&config);
     if (PyStatus_Exception(status)) {
@@ -780,7 +764,6 @@ static int test_init_isolated_flag(void)
 
     /* Test PyConfig.isolated=1 */
     PyConfig config;
-    config.struct_size = sizeof(PyConfig);
 
     status = PyConfig_InitPythonConfig(&config);
     if (PyStatus_Exception(status)) {
@@ -803,25 +786,17 @@ static int test_init_isolated_flag(void)
 /* PyPreConfig.isolated=1, PyConfig.isolated=0 */
 static int test_preinit_isolated1(void)
 {
-    PyStatus status;
-
     PyPreConfig preconfig;
-    preconfig.struct_size = sizeof(PyPreConfig);
-
-    status = _PyPreConfig_InitCompatConfig(&preconfig);
-    if (PyStatus_Exception(status)) {
-        Py_ExitStatusException(status);
-    }
+    _PyPreConfig_InitCompatConfig(&preconfig);
 
     preconfig.isolated = 1;
 
-    status = Py_PreInitialize(&preconfig);
+    PyStatus status = Py_PreInitialize(&preconfig);
     if (PyStatus_Exception(status)) {
         Py_ExitStatusException(status);
     }
 
     PyConfig config;
-    config.struct_size = sizeof(PyConfig);
 
     status = _PyConfig_InitCompatConfig(&config);
     if (PyStatus_Exception(status)) {
@@ -840,26 +815,19 @@ static int test_preinit_isolated1(void)
 /* PyPreConfig.isolated=0, PyConfig.isolated=1 */
 static int test_preinit_isolated2(void)
 {
-    PyStatus status;
-
     PyPreConfig preconfig;
-    preconfig.struct_size = sizeof(PyPreConfig);
-
-    status = _PyPreConfig_InitCompatConfig(&preconfig);
-    if (PyStatus_Exception(status)) {
-        Py_ExitStatusException(status);
-    }
+    _PyPreConfig_InitCompatConfig(&preconfig);
 
     preconfig.isolated = 0;
 
-    status = Py_PreInitialize(&preconfig);
+    PyStatus status = Py_PreInitialize(&preconfig);
     if (PyStatus_Exception(status)) {
         Py_ExitStatusException(status);
     }
 
     /* Test PyConfig.isolated=1 */
     PyConfig config;
-    config.struct_size = sizeof(PyConfig);
+
     status = _PyConfig_InitCompatConfig(&config);
     if (PyStatus_Exception(status)) {
         Py_ExitStatusException(status);
@@ -880,15 +848,8 @@ static int test_preinit_isolated2(void)
 
 static int test_preinit_dont_parse_argv(void)
 {
-    PyStatus status;
-
     PyPreConfig preconfig;
-    preconfig.struct_size = sizeof(PyPreConfig);
-
-    status = PyPreConfig_InitIsolatedConfig(&preconfig);
-    if (PyStatus_Exception(status)) {
-        Py_ExitStatusException(status);
-    }
+    PyPreConfig_InitIsolatedConfig(&preconfig);
 
     preconfig.isolated = 0;
 
@@ -899,13 +860,13 @@ static int test_preinit_dont_parse_argv(void)
                        L"-X", L"dev",
                        L"-X", L"utf8",
                        L"script.py"};
-    status = Py_PreInitializeFromArgs(&preconfig, Py_ARRAY_LENGTH(argv), argv);
+    PyStatus status = Py_PreInitializeFromArgs(&preconfig,
+                                               Py_ARRAY_LENGTH(argv), argv);
     if (PyStatus_Exception(status)) {
         Py_ExitStatusException(status);
     }
 
     PyConfig config;
-    config.struct_size = sizeof(PyConfig);
 
     status = PyConfig_InitIsolatedConfig(&config);
     if (PyStatus_Exception(status)) {
@@ -931,7 +892,6 @@ static int test_preinit_parse_argv(void)
 {
     PyStatus status;
     PyConfig config;
-    config.struct_size = sizeof(PyConfig);
 
     status = PyConfig_InitPythonConfig(&config);
     if (PyStatus_Exception(status)) {
@@ -989,12 +949,7 @@ static int check_preinit_isolated_config(int preinit)
 
     if (preinit) {
         PyPreConfig preconfig;
-        preconfig.struct_size = sizeof(PyPreConfig);
-
-        status = PyPreConfig_InitIsolatedConfig(&preconfig);
-        if (PyStatus_Exception(status)) {
-            Py_ExitStatusException(status);
-        }
+        PyPreConfig_InitIsolatedConfig(&preconfig);
 
         status = Py_PreInitialize(&preconfig);
         if (PyStatus_Exception(status)) {
@@ -1007,7 +962,6 @@ static int check_preinit_isolated_config(int preinit)
     }
 
     PyConfig config;
-    config.struct_size = sizeof(PyConfig);
 
     status = PyConfig_InitIsolatedConfig(&config);
     if (PyStatus_Exception(status)) {
@@ -1058,12 +1012,7 @@ static int check_init_python_config(int preinit)
 
     if (preinit) {
         PyPreConfig preconfig;
-        preconfig.struct_size = sizeof(PyPreConfig);
-
-        status = PyPreConfig_InitPythonConfig(&preconfig);
-        if (PyStatus_Exception(status)) {
-            Py_ExitStatusException(status);
-        }
+        PyPreConfig_InitPythonConfig(&preconfig);
 
         status = Py_PreInitialize(&preconfig);
         if (PyStatus_Exception(status)) {
@@ -1072,7 +1021,6 @@ static int check_init_python_config(int preinit)
     }
 
     PyConfig config;
-    config.struct_size = sizeof(PyConfig);
 
     status = PyConfig_InitPythonConfig(&config);
     if (PyStatus_Exception(status)) {
@@ -1101,27 +1049,19 @@ static int test_init_python_config(void)
 
 static int test_init_dont_configure_locale(void)
 {
-    PyStatus status;
-
     PyPreConfig preconfig;
-    preconfig.struct_size = sizeof(PyPreConfig);
-
-    status = PyPreConfig_InitPythonConfig(&preconfig);
-    if (PyStatus_Exception(status)) {
-        Py_ExitStatusException(status);
-    }
+    PyPreConfig_InitPythonConfig(&preconfig);
 
     preconfig.configure_locale = 0;
     preconfig.coerce_c_locale = 1;
     preconfig.coerce_c_locale_warn = 1;
 
-    status = Py_PreInitialize(&preconfig);
+    PyStatus status = Py_PreInitialize(&preconfig);
     if (PyStatus_Exception(status)) {
         Py_ExitStatusException(status);
     }
 
     PyConfig config;
-    config.struct_size = sizeof(PyConfig);
 
     status = PyConfig_InitPythonConfig(&config);
     if (PyStatus_Exception(status)) {
@@ -1140,7 +1080,6 @@ static int test_init_dev_mode(void)
 {
     PyStatus status;
     PyConfig config;
-    config.struct_size = sizeof(PyConfig);
 
     status = PyConfig_InitPythonConfig(&config);
     if (PyStatus_Exception(status)) {
@@ -1365,7 +1304,6 @@ static int run_audit_run_test(int argc, wchar_t **argv, void *test)
 {
     PyStatus status;
     PyConfig config;
-    config.struct_size = sizeof(PyConfig);
 
     status = PyConfig_InitPythonConfig(&config);
     if (PyStatus_Exception(status)) {
@@ -1415,7 +1353,6 @@ static int test_init_read_set(void)
 {
     PyStatus status;
     PyConfig config;
-    config.struct_size = sizeof(PyConfig);
 
     status = PyConfig_InitPythonConfig(&config);
     if (PyStatus_Exception(status)) {
@@ -1465,7 +1402,6 @@ static int test_init_sys_add(void)
     PySys_AddWarnOption(L"ignore:::sysadd_warnoption");
 
     PyConfig config;
-    config.struct_size = sizeof(PyConfig);
 
     PyStatus status;
     status = PyConfig_InitPythonConfig(&config);
@@ -1533,18 +1469,12 @@ static int test_init_setpath(void)
 
 static int test_init_setpath_config(void)
 {
-    PyStatus status;
     PyPreConfig preconfig;
-    preconfig.struct_size = sizeof(PyPreConfig);
-
-    status = PyPreConfig_InitPythonConfig(&preconfig);
-    if (PyStatus_Exception(status)) {
-        Py_ExitStatusException(status);
-    }
+    PyPreConfig_InitPythonConfig(&preconfig);
 
     /* Explicitly preinitializes with Python preconfiguration to avoid
       Py_SetPath() implicit preinitialization with compat preconfiguration. */
-    status = Py_PreInitialize(&preconfig);
+    PyStatus status = Py_PreInitialize(&preconfig);
     if (PyStatus_Exception(status)) {
         Py_ExitStatusException(status);
     }
@@ -1564,7 +1494,6 @@ static int test_init_setpath_config(void)
     putenv("TESTPATH=");
 
     PyConfig config;
-    config.struct_size = sizeof(PyConfig);
 
     status = PyConfig_InitPythonConfig(&config);
     if (PyStatus_Exception(status)) {
@@ -1612,7 +1541,6 @@ static int test_init_warnoptions(void)
     PySys_AddWarnOption(L"ignore:::PySys_AddWarnOption2");
 
     PyConfig config;
-    config.struct_size = sizeof(PyConfig);
 
     status = PyConfig_InitPythonConfig(&config);
     if (PyStatus_Exception(status)) {
@@ -1680,7 +1608,6 @@ static int test_init_run_main(void)
 {
     PyStatus status;
     PyConfig config;
-    config.struct_size = sizeof(PyConfig);
 
     status = PyConfig_InitPythonConfig(&config);
     if (PyStatus_Exception(status)) {
@@ -1697,7 +1624,6 @@ static int test_init_main(void)
 {
     PyStatus status;
     PyConfig config;
-    config.struct_size = sizeof(PyConfig);
 
     status = PyConfig_InitPythonConfig(&config);
     if (PyStatus_Exception(status)) {
@@ -1729,7 +1655,6 @@ static int test_run_main(void)
 {
     PyStatus status;
     PyConfig config;
-    config.struct_size = sizeof(PyConfig);
 
     status = PyConfig_InitPythonConfig(&config);
     if (PyStatus_Exception(status)) {
diff --git a/Python/frozenmain.c b/Python/frozenmain.c
index 76309e9e5da..c56938ab489 100644
--- a/Python/frozenmain.c
+++ b/Python/frozenmain.c
@@ -40,7 +40,6 @@ Py_FrozenMain(int argc, char **argv)
     }
 
     PyConfig config;
-    config.struct_size = sizeof(PyConfig);
     status = PyConfig_InitPythonConfig(&config);
     if (PyStatus_Exception(status)) {
         PyConfig_Clear(&config);
diff --git a/Python/initconfig.c b/Python/initconfig.c
index dec4bf2e4d5..107429c7ec3 100644
--- a/Python/initconfig.c
+++ b/Python/initconfig.c
@@ -529,17 +529,6 @@ Py_GetArgcArgv(int *argc, wchar_t ***argv)
      : _PyStatus_NO_MEMORY())
 
 
-static PyStatus
-config_check_struct_size(const PyConfig *config)
-{
-    if (config->struct_size != sizeof(PyConfig)) {
-        return _PyStatus_ERR("unsupported PyConfig structure size "
-                             "(Python version mismatch?)");
-    }
-    return _PyStatus_OK();
-}
-
-
 /* Free memory allocated in config, but don't clear all attributes */
 void
 PyConfig_Clear(PyConfig *config)
@@ -583,15 +572,7 @@ PyConfig_Clear(PyConfig *config)
 PyStatus
 _PyConfig_InitCompatConfig(PyConfig *config)
 {
-    size_t struct_size = config->struct_size;
     memset(config, 0, sizeof(*config));
-    config->struct_size = struct_size;
-
-    PyStatus status = config_check_struct_size(config);
-    if (_PyStatus_EXCEPTION(status)) {
-        _PyStatus_UPDATE_FUNC(status);
-        return status;
-    }
 
     config->_config_init = (int)_PyConfig_INIT_COMPAT;
     config->isolated = -1;
@@ -775,18 +756,6 @@ _PyConfig_Copy(PyConfig *config, const PyConfig *config2)
 {
     PyStatus status;
 
-    status = config_check_struct_size(config);
-    if (_PyStatus_EXCEPTION(status)) {
-        _PyStatus_UPDATE_FUNC(status);
-        return status;
-    }
-
-    status = config_check_struct_size(config2);
-    if (_PyStatus_EXCEPTION(status)) {
-        _PyStatus_UPDATE_FUNC(status);
-        return status;
-    }
-
     PyConfig_Clear(config);
 
 #define COPY_ATTR(ATTR) config->ATTR = config2->ATTR
@@ -2280,7 +2249,6 @@ core_read_precmdline(PyConfig *config, _PyPreCmdline *precmdline)
     }
 
     PyPreConfig preconfig;
-    preconfig.struct_size = sizeof(PyPreConfig);
 
     status = _PyPreConfig_InitFromPreConfig(&preconfig, &_PyRuntime.preconfig);
     if (_PyStatus_EXCEPTION(status)) {
@@ -2475,12 +2443,6 @@ PyConfig_Read(PyConfig *config)
     PyStatus status;
     PyWideStringList orig_argv = _PyWideStringList_INIT;
 
-    status = config_check_struct_size(config);
-    if (_PyStatus_EXCEPTION(status)) {
-        _PyStatus_UPDATE_FUNC(status);
-        return status;
-    }
-
     status = _Py_PreInitializeFromConfig(config, NULL);
     if (_PyStatus_EXCEPTION(status)) {
         return status;
diff --git a/Python/pathconfig.c b/Python/pathconfig.c
index 6886ab7c42d..5550194a5d5 100644
--- a/Python/pathconfig.c
+++ b/Python/pathconfig.c
@@ -434,7 +434,6 @@ pathconfig_global_read(_PyPathConfig *pathconfig)
 {
     PyStatus status;
     PyConfig config;
-    config.struct_size = sizeof(PyConfig);
 
     status = _PyConfig_InitCompatConfig(&config);
     if (_PyStatus_EXCEPTION(status)) {
diff --git a/Python/preconfig.c b/Python/preconfig.c
index 01c72f5d6ba..89a6227fa67 100644
--- a/Python/preconfig.c
+++ b/Python/preconfig.c
@@ -269,29 +269,10 @@ _PyPreCmdline_Read(_PyPreCmdline *cmdline, const PyPreConfig *preconfig)
 /* --- PyPreConfig ----------------------------------------------- */
 
 
-static PyStatus
-preconfig_check_struct_size(PyPreConfig *config)
-{
-    if (config->struct_size != sizeof(PyPreConfig)) {
-        return _PyStatus_ERR("unsupported PyPreConfig structure size "
-                             "(Python version mismatch?)");
-    }
-    return _PyStatus_OK();
-}
-
-
-PyStatus
+void
 _PyPreConfig_InitCompatConfig(PyPreConfig *config)
 {
-    size_t struct_size = config->struct_size;
     memset(config, 0, sizeof(*config));
-    config->struct_size = struct_size;
-
-    PyStatus status = preconfig_check_struct_size(config);
-    if (_PyStatus_EXCEPTION(status)) {
-        _PyStatus_UPDATE_FUNC(status);
-        return status;
-    }
 
     config->_config_init = (int)_PyConfig_INIT_COMPAT;
     config->parse_argv = 0;
@@ -313,18 +294,13 @@ _PyPreConfig_InitCompatConfig(PyPreConfig *config)
 #ifdef MS_WINDOWS
     config->legacy_windows_fs_encoding = -1;
 #endif
-    return _PyStatus_OK();
 }
 
 
-PyStatus
+void
 PyPreConfig_InitPythonConfig(PyPreConfig *config)
 {
-    PyStatus status = _PyPreConfig_InitCompatConfig(config);
-    if (_PyStatus_EXCEPTION(status)) {
-        _PyStatus_UPDATE_FUNC(status);
-        return status;
-    }
+    _PyPreConfig_InitCompatConfig(config);
 
     config->_config_init = (int)_PyConfig_INIT_PYTHON;
     config->isolated = 0;
@@ -339,18 +315,13 @@ PyPreConfig_InitPythonConfig(PyPreConfig *config)
 #ifdef MS_WINDOWS
     config->legacy_windows_fs_encoding = 0;
 #endif
-    return _PyStatus_OK();
 }
 
 
-PyStatus
+void
 PyPreConfig_InitIsolatedConfig(PyPreConfig *config)
 {
-    PyStatus status = _PyPreConfig_InitCompatConfig(config);
-    if (_PyStatus_EXCEPTION(status)) {
-        _PyStatus_UPDATE_FUNC(status);
-        return status;
-    }
+    _PyPreConfig_InitCompatConfig(config);
 
     config->_config_init = (int)_PyConfig_INIT_ISOLATED;
     config->configure_locale = 0;
@@ -361,7 +332,6 @@ PyPreConfig_InitIsolatedConfig(PyPreConfig *config)
 #ifdef MS_WINDOWS
     config->legacy_windows_fs_encoding = 0;
 #endif
-    return _PyStatus_OK();
 }
 
 
@@ -369,47 +339,35 @@ PyStatus
 _PyPreConfig_InitFromPreConfig(PyPreConfig *config,
                                const PyPreConfig *config2)
 {
-    PyStatus status = PyPreConfig_InitPythonConfig(config);
-    if (_PyStatus_EXCEPTION(status)) {
-        return status;
-    }
-
+    PyPreConfig_InitPythonConfig(config);
     preconfig_copy(config, config2);
     return _PyStatus_OK();
 }
 
 
-PyStatus
+void
 _PyPreConfig_InitFromConfig(PyPreConfig *preconfig, const PyConfig *config)
 {
-    PyStatus status;
     _PyConfigInitEnum config_init = (_PyConfigInitEnum)config->_config_init;
     switch (config_init) {
     case _PyConfig_INIT_PYTHON:
-        status = PyPreConfig_InitPythonConfig(preconfig);
+        PyPreConfig_InitPythonConfig(preconfig);
         break;
     case _PyConfig_INIT_ISOLATED:
-        status = PyPreConfig_InitIsolatedConfig(preconfig);
+        PyPreConfig_InitIsolatedConfig(preconfig);
         break;
     case _PyConfig_INIT_COMPAT:
     default:
-        status = _PyPreConfig_InitCompatConfig(preconfig);
-    }
-
-    if (_PyStatus_EXCEPTION(status)) {
-        return status;
+        _PyPreConfig_InitCompatConfig(preconfig);
     }
 
     _PyPreConfig_GetConfig(preconfig, config);
-    return _PyStatus_OK();
 }
 
 
 static void
 preconfig_copy(PyPreConfig *config, const PyPreConfig *config2)
 {
-    assert(config->struct_size == sizeof(PyPreConfig));
-
 #define COPY_ATTR(ATTR) config->ATTR = config2->ATTR
 
     COPY_ATTR(_config_init);
@@ -829,12 +787,6 @@ _PyPreConfig_Read(PyPreConfig *config, const _PyArgv *args)
         return status;
     }
 
-    status = preconfig_check_struct_size(config);
-    if (_PyStatus_EXCEPTION(status)) {
-        _PyStatus_UPDATE_FUNC(status);
-        return status;
-    }
-
     preconfig_get_global_vars(config);
 
     /* Copy LC_CTYPE locale, since it's modified later */
@@ -849,7 +801,6 @@ _PyPreConfig_Read(PyPreConfig *config, const _PyArgv *args)
 
     /* Save the config to be able to restore it if encodings change */
     PyPreConfig save_config;
-    save_config.struct_size = sizeof(PyPreConfig);
 
     status = _PyPreConfig_InitFromPreConfig(&save_config, config);
     if (_PyStatus_EXCEPTION(status)) {
@@ -976,7 +927,6 @@ PyStatus
 _PyPreConfig_Write(const PyPreConfig *src_config)
 {
     PyPreConfig config;
-    config.struct_size = sizeof(PyPreConfig);
 
     PyStatus status = _PyPreConfig_InitFromPreConfig(&config, src_config);
     if (_PyStatus_EXCEPTION(status)) {
diff --git a/Python/pylifecycle.c b/Python/pylifecycle.c
index ea0d7a5ee2b..019c56c3f8b 100644
--- a/Python/pylifecycle.c
+++ b/Python/pylifecycle.c
@@ -735,7 +735,6 @@ _Py_PreInitializeFromPyArgv(const PyPreConfig *src_config, const _PyArgv *args)
     runtime->preinitializing = 1;
 
     PyPreConfig config;
-    config.struct_size = sizeof(PyPreConfig);
 
     status = _PyPreConfig_InitFromPreConfig(&config, src_config);
     if (_PyStatus_EXCEPTION(status)) {
@@ -799,12 +798,8 @@ _Py_PreInitializeFromConfig(const PyConfig *config,
     }
 
     PyPreConfig preconfig;
-    preconfig.struct_size = sizeof(PyPreConfig);
 
-    status = _PyPreConfig_InitFromConfig(&preconfig, config);
-    if (_PyStatus_EXCEPTION(status)) {
-        return status;
-    }
+    _PyPreConfig_InitFromConfig(&preconfig, config);
 
     if (!config->parse_argv) {
         return Py_PreInitialize(&preconfig);
@@ -852,7 +847,6 @@ pyinit_core(_PyRuntimeState *runtime,
     }
 
     PyConfig config;
-    config.struct_size = sizeof(PyConfig);
 
     status = _PyConfig_InitCompatConfig(&config);
     if (_PyStatus_EXCEPTION(status)) {
@@ -1079,7 +1073,6 @@ Py_InitializeEx(int install_sigs)
     }
 
     PyConfig config;
-    config.struct_size = sizeof(PyConfig);
 
     status = _PyConfig_InitCompatConfig(&config);
     if (_PyStatus_EXCEPTION(status)) {
diff --git a/Python/pystate.c b/Python/pystate.c
index 0f0cb229955..69b86ce4f7a 100644
--- a/Python/pystate.c
+++ b/Python/pystate.c
@@ -61,11 +61,7 @@ _PyRuntimeState_Init_impl(_PyRuntimeState *runtime)
     _PyGC_Initialize(&runtime->gc);
     _PyEval_Initialize(&runtime->ceval);
 
-    runtime->preconfig.struct_size = sizeof(PyPreConfig);
-    PyStatus status = PyPreConfig_InitPythonConfig(&runtime->preconfig);
-    if (_PyStatus_EXCEPTION(status)) {
-        return status;
-    }
+    PyPreConfig_InitPythonConfig(&runtime->preconfig);
 
     runtime->gilstate.check_enabled = 1;
 
@@ -209,7 +205,6 @@ PyInterpreterState_New(void)
     memset(interp, 0, sizeof(*interp));
     interp->id_refcount = -1;
 
-    interp->config.struct_size = sizeof(PyConfig);
     PyStatus status = PyConfig_InitPythonConfig(&interp->config);
     if (_PyStatus_EXCEPTION(status)) {
         /* Don't report status to caller: PyConfig_InitPythonConfig()