diff --git a/Python/modsupport.c b/Python/modsupport.c
index 7dbfe1ce7d4..dacc1a0a815 100644
--- a/Python/modsupport.c
+++ b/Python/modsupport.c
@@ -47,6 +47,8 @@ Py_InitModule4(char *name, PyMethodDef *methods, char *doc,
 {
 	PyObject *m, *d, *v;
 	PyMethodDef *ml;
+	if (!Py_IsInitialized())
+	    Py_FatalError("Interpreter not initialized (version mismatch?)");
 	if (module_api_version != PYTHON_API_VERSION)
 		fprintf(stderr, api_version_warning,
 			name, PYTHON_API_VERSION, name, module_api_version);