diff --git a/reactos/include/host/typedefs.h b/reactos/include/host/typedefs.h
index 7a103f7e549..cb73137e4f9 100644
--- a/reactos/include/host/typedefs.h
+++ b/reactos/include/host/typedefs.h
@@ -231,6 +231,5 @@ typedef const UNICODE_STRING *PCUNICODE_STRING;
 /* Prevent inclusion of some other headers */
 #define __INTERNAL_DEBUG
 #define RTL_H
-#define _TYPEDEFS64_H
 
 #endif