diff --git a/reactos/ntoskrnl/mm/ARM3/ncache.c b/reactos/ntoskrnl/mm/ARM3/ncache.c
index 348ba557d94..f120fd307f8 100644
--- a/reactos/ntoskrnl/mm/ARM3/ncache.c
+++ b/reactos/ntoskrnl/mm/ARM3/ncache.c
@@ -170,7 +170,7 @@ MmAllocateNonCachedMemory(IN SIZE_T NumberOfBytes)
 VOID
 NTAPI
 MmFreeNonCachedMemory(IN PVOID BaseAddress,
-                      IN ULONG NumberOfBytes)
+                      IN SIZE_T NumberOfBytes)
 {
     PMDL Mdl;
     PMMPTE PointerPte;