diff --git a/reactos/dll/directx/ksuser/ksuser.h b/reactos/dll/directx/ksuser/ksuser.h
index 69a83aa73ca..1d60b17c611 100644
--- a/reactos/dll/directx/ksuser/ksuser.h
+++ b/reactos/dll/directx/ksuser/ksuser.h
@@ -10,14 +10,6 @@
 
 #include <ks.h>
 
-LPVOID
-__stdcall
-HeapAlloc(
-  HANDLE hHeap,
-  DWORD dwFlags,
-  DWORD dwBytes
-);
-
 #define ROUND_DOWN(n, align) \
     (((ULONG)n) & ~((align) - 1l))