diff --git a/reactos/ChangeLog b/reactos/ChangeLog
index 1ac4c6cf62a..a0822deaa85 100644
--- a/reactos/ChangeLog
+++ b/reactos/ChangeLog
@@ -1,3 +1,8 @@
+2003-03-16  Casper S. Hornstrup  <chorns@users.sourceforge.net>
+
+	* include/ntos/types.h (FALSE): Protect with #ifndef FALSE.
+	(TRUE): Protect with #ifndef TRUE.
+
 2003-03-16  Casper S. Hornstrup  <chorns@users.sourceforge.net>
 
 	* include/napi/i386/segment.h (put_user, get_user,
diff --git a/reactos/include/ntos/types.h b/reactos/include/ntos/types.h
index 3efeef39e20..1987799eb90 100644
--- a/reactos/include/ntos/types.h
+++ b/reactos/include/ntos/types.h
@@ -231,8 +231,12 @@ typedef unsigned short *PRTL_ATOM;
 
 #endif /* __USE_W32API */
 
+#ifndef FALSE
 #define FALSE 0
+#endif
+#ifndef TRUE
 #define TRUE 1
+#endif
 
 #ifndef NULL
 #ifdef __cplusplus