Index: Python/sysmodule.c
===================================================================
--- Python/sysmodule.c	(revision 62635)
+++ Python/sysmodule.c	(working copy)
@@ -579,6 +579,36 @@
 	                     ver.szCSDVersion);
 }
 
+PyDoc_STRVAR(iswow64process_doc,
+"iswow64process()\n\
+\n\
+Returns True if this is a 32bit process running on a 64bit Windows.\n\
+This is a thin wrapper around the win32 API IsWow64Process() and False is\n\
+returned if that is not available for this version of Windows.  If the\n\
+function exists but fails, a WindowsError will be thrown.\n\
+"
+);
+
+static PyObject *
+sys_iswow64process(PyObject *self)
+{
+	BOOL bIsWow64 = FALSE;
+	typedef BOOL (WINAPI *IsWow64Processfunc)(HANDLE, PBOOL);
+	IsWow64Processfunc pfnIsWow64Process = NULL;
+
+	// Kernel32.dll is already used by Python.
+	HMODULE hmodule=GetModuleHandle("Kernel32.dll");
+	if (hmodule)
+		pfnIsWow64Process=(IsWow64Processfunc)
+			GetProcAddress(hmodule, "IsWow64Process");
+	if (pfnIsWow64Process) {
+		if (!(*pfnIsWow64Process)(GetCurrentProcess(), &bIsWow64)) {
+			return PyErr_SetFromWindowsErr(0);
+		}
+	}
+	return PyBool_FromLong(bIsWow64);
+}
+
 #endif /* MS_WINDOWS */
 
 #ifdef HAVE_DLOPEN
@@ -854,6 +884,8 @@
 #ifdef MS_WINDOWS
 	{"getwindowsversion", (PyCFunction)sys_getwindowsversion, METH_NOARGS,
 	 getwindowsversion_doc},
+	{"iswow64process", (PyCFunction)sys_iswow64process, METH_NOARGS,
+	 iswow64process_doc},
 #endif /* MS_WINDOWS */
 #ifdef USE_MALLOPT
 	{"mdebug",	sys_mdebug, METH_VARARGS},
Index: Misc/NEWS
===================================================================
--- Misc/NEWS	(revision 62635)
+++ Misc/NEWS	(working copy)
@@ -47,6 +47,8 @@
 Library
 -------
 
+- Add sys.iswow64process() on Windows platforms.
+
 - Issue #2635: Fix bug in 'fix_sentence_endings' textwrap.fill option,
   where an extra space was added after a word containing (but not
   ending in) '.', '!' or '?'.
Index: Doc/library/sys.rst
===================================================================
--- Doc/library/sys.rst	(revision 62635)
+++ Doc/library/sys.rst	(working copy)
@@ -475,7 +475,18 @@
 
    .. versionadded:: 2.3
 
+.. function:: iswow64process()
 
+   Returns True if this is a 32bit process running on a 64bit Windows.
+   This is a thin wrapper around the win32 API IsWow64Process() and False is
+   returned if that is not available for this version of Windows.  If the
+   function exists but fails, a WindowsError will be thrown.
+
+   Availability: Windows.
+
+   .. versionadded:: 2.6
+
+
 .. data:: hexversion
 
    The version number encoded as a single integer.  This is guaranteed to increase
Index: Lib/test/test_sys.py
===================================================================
--- Lib/test/test_sys.py	(revision 62635)
+++ Lib/test/test_sys.py	(working copy)
@@ -209,6 +209,16 @@
             self.assert_(isinstance(v[3], int))
             self.assert_(isinstance(v[4], str))
 
+    def test_iswow64process(self):
+        if hasattr(sys, "iswow64process"):
+            v = sys.iswow64process()
+            # it is a little hard to test is the result is correct - do
+            # what we can though.
+            # If v is true, we must be a 32bit process.
+            if v:
+                self.assert_("32 bit" in sys.version)
+            # else ???
+
     def test_dlopenflags(self):
         if hasattr(sys, "setdlopenflags"):
             self.assert_(hasattr(sys, "getdlopenflags"))