diff --git a/basis/windows/types/types.factor b/basis/windows/types/types.factor
index cf21f74fd8..9aeec7f228 100644
--- a/basis/windows/types/types.factor
+++ b/basis/windows/types/types.factor
@@ -40,7 +40,7 @@ TYPEDEF: intptr_t            LONG_PTR
 TYPEDEF: intptr_t*           PLONG_PTR
 
 TYPEDEF: uint                ULONG
-TYPEDEF: void*               ULONG_PTR
+TYPEDEF: uintptr_t           ULONG_PTR
 TYPEDEF: void*               PULONG_PTR
 
 TYPEDEF: void                VOID