diff --git a/lib/libc/sys/umask.2 b/lib/libc/sys/umask.2
index 2f91719ed7c3..237eb0306ab3 100644
--- a/lib/libc/sys/umask.2
+++ b/lib/libc/sys/umask.2
@@ -30,7 +30,7 @@
 .\" SUCH DAMAGE.
 .\"
 .\"     from: @(#)umask.2	6.2 (Berkeley) 3/10/91
-.\"	$Id: umask.2,v 1.2 1993/08/01 07:42:05 mycroft Exp $
+.\"	$Id: umask.2,v 1.3 1993/10/05 16:38:01 jtc Exp $
 .\"
 .Dd March 10, 1991
 .Dt UMASK 2
@@ -39,6 +39,7 @@
 .Nm umask
 .Nd set file creation mode mask
 .Sh SYNOPSIS
+.Fd #include <sys/types.h>
 .Fd #include <sys/stat.h>
 .Ft mode_t
 .Fn umask "mode_t numask"