diff --git a/Modules/_ctypes/stgdict.c b/Modules/_ctypes/stgdict.c
index b4a6e87f8c4..fd6f5e25577 100644
--- a/Modules/_ctypes/stgdict.c
+++ b/Modules/_ctypes/stgdict.c
@@ -457,11 +457,13 @@ StructUnionType_update_stgdict(PyObject *type, PyObject *fields, int isStruct)
 
 		if (!prop) {
 			Py_DECREF(pair);
+			Py_DECREF((PyObject *)stgdict);
 			return -1;
 		}
 		if (-1 == PyDict_SetItem(realdict, name, prop)) {
 			Py_DECREF(prop);
 			Py_DECREF(pair);
+			Py_DECREF((PyObject *)stgdict);
 			return -1;
 		}
 		Py_DECREF(pair);