diff --git a/reactos/include/ndk/rtltypes.h b/reactos/include/ndk/rtltypes.h
index 82fabdbe7d7..70cc9f12240 100644
--- a/reactos/include/ndk/rtltypes.h
+++ b/reactos/include/ndk/rtltypes.h
@@ -399,7 +399,7 @@ typedef struct _RTL_ATOM_TABLE
 } RTL_ATOM_TABLE, *PRTL_ATOM_TABLE;
 
 /* Let Kernel Drivers use this */
-#ifndef _WINBASE_
+#ifndef _WINBASE_H
     typedef struct _SYSTEMTIME
     {
         WORD wYear;
diff --git a/reactos/w32api/include/winbase.h b/reactos/w32api/include/winbase.h
index b8ac339e5aa..59b47fc1abd 100644
--- a/reactos/w32api/include/winbase.h
+++ b/reactos/w32api/include/winbase.h
@@ -1,5 +1,5 @@
-#ifndef _WINBASE_
-#define _WINBASE_
+#ifndef _WINBASE_H
+#define _WINBASE_H
 #if __GNUC__ >= 3
 #pragma GCC system_header
 #endif