diff --git a/Include/objimpl.h b/Include/objimpl.h
index 139e337..724ba98 100644
--- a/Include/objimpl.h
+++ b/Include/objimpl.h
@@ -47,12 +47,26 @@
 n * tp_itemsize.  This fills in the ob_size field as well.
 */
 
+#ifndef MS_COREDLL
 extern PyObject *_PyObject_New Py_PROTO((PyTypeObject *));
 extern varobject *_PyObject_NewVar Py_PROTO((PyTypeObject *, int));
 
 #define PyObject_NEW(type, typeobj) ((type *) _PyObject_New(typeobj))
 #define PyObject_NEW_VAR(type, typeobj, n) ((type *) _PyObject_NewVar(typeobj, n))
 
+#else
+/* For an MS-Windows DLL, we change the way an object is created, so that the
+   extension module's malloc is used, rather than the core DLL malloc, as there is
+   no guarantee they will use the same heap
+*/
+extern PyObject *_PyObject_New Py_PROTO((PyTypeObject *, PyObject *));
+extern varobject *_PyObject_NewVar Py_PROTO((PyTypeObject *, int, varobject *));
+
+#define PyObject_NEW(type, typeobj) ((type *) _PyObject_New(typeobj,(PyObject *)malloc((typeobj)->tp_basicsize)))
+#define PyObject_NEW_VAR(type, typeobj, n) ((type *) _PyObject_NewVar(typeobj, n, (varobject *)malloc((typeobj)->tp_basicsize + n * (typeobj)->tp_itemsize)))
+
+#endif /* MS_COREDLL */
+
 #ifdef __cplusplus
 }
 #endif