diff --git a/Tk/tkImaging.c b/Tk/tkImaging.c
index 494349a8e..f82fc2007 100644
--- a/Tk/tkImaging.c
+++ b/Tk/tkImaging.c
@@ -60,7 +60,11 @@ ImagingFind(const char* name)
     Py_ssize_t id;
 
     /* FIXME: use CObject instead? */
+#if defined(_MSC_VER) && defined(_WIN64)
+    id = _atoi64(name);
+#else
     id = atol(name);
+#endif
     if (!id)
 	return NULL;