diff --git a/basis/windows/time/time.factor b/basis/windows/time/time.factor
index 5ffc62680e..54a7a8e32a 100644
--- a/basis/windows/time/time.factor
+++ b/basis/windows/time/time.factor
@@ -1,7 +1,7 @@
 ! Copyright (C) 2007 Doug Coleman.
 ! See http://factorcode.org/license.txt for BSD license.
 USING: alien alien.c-types kernel math windows windows.kernel32
-namespaces calendar ;
+namespaces calendar math.bitwise ;
 IN: windows.time
 
 : >64bit ( lo hi -- n )