diff --git a/Xw32defs.h b/Xw32defs.h
index 07624fe..f65b265 100644
--- a/Xw32defs.h
+++ b/Xw32defs.h
@@ -44,7 +44,7 @@ typedef char *caddr_t;
 #define putenv	    _putenv
 #define read	   _read
 #define rmdir	_rmdir
-#define sleep(x) _sleep((x) * 1000)
+#define sleep(x) Sleep((x) * 1000)
 #define stat	 _stat
 #define sys_errlist _sys_errlist
 #define sys_nerr    _sys_nerr
diff --git a/Xwindows.h b/Xwindows.h
index 7fb9840..8364952 100644
--- a/Xwindows.h
+++ b/Xwindows.h
@@ -66,7 +66,7 @@ The Open Group.
 #define RT_CURSOR       ((RESTYPE)5)
 #endif
 
-#define sleep(x) Sleep(1000*x)
+#define sleep(x) Sleep((x) * 1000)
 
 #if defined(WIN32) && (!defined(PATH_MAX) || PATH_MAX < 1024)
 #undef PATH_MAX