diff --git a/share/man/man9/ratecheck.9 b/share/man/man9/ratecheck.9
index ef60184a91a2..fc265075be27 100644
--- a/share/man/man9/ratecheck.9
+++ b/share/man/man9/ratecheck.9
@@ -1,4 +1,4 @@
-.\" $NetBSD: ratecheck.9,v 1.3 2000/08/02 23:43:52 itojun Exp $
+.\" $NetBSD: ratecheck.9,v 1.4 2000/08/02 23:51:07 itojun Exp $
 .\"
 .\" Copyright (c) 2000 The NetBSD Foundation, Inc.
 .\" All rights reserved.
@@ -139,3 +139,9 @@ The
 .Fn ratecheck
 function appeared in
 .Nx 1.5 .
+.Sh BUGS
+.Fn ratecheck
+may not work as expected, if
+.Fa mininterval
+is less than the hardware clock interrupt interval
+.Pq Li 1/hz .