diff --git a/bin/mkdir/mkdir.c b/bin/mkdir/mkdir.c
index 083a2af7975..2f09c3d8b3e 100644
--- a/bin/mkdir/mkdir.c
+++ b/bin/mkdir/mkdir.c
@@ -123,7 +123,7 @@ build(path)
 	char *p;
 
 	p = path;
-        oumask = (mode_t)NULL;
+	oumask = 0;
 	if (p[0] == '/')		/* Skip leading '/'. */
 		++p;
 	for (first = 1;; ++p) {