diff --git a/usr.sbin/envstat/envstat.8 b/usr.sbin/envstat/envstat.8
index c95ee6de424a..738618cc00dc 100644
--- a/usr.sbin/envstat/envstat.8
+++ b/usr.sbin/envstat/envstat.8
@@ -1,4 +1,4 @@
-.\"	$NetBSD: envstat.8,v 1.17 2007/07/02 20:37:06 xtraeme Exp $
+.\"	$NetBSD: envstat.8,v 1.18 2007/07/04 17:15:03 xtraeme Exp $
 .\"
 .\" Copyright (c) 2000, 2007 The NetBSD Foundation, Inc.
 .\" All rights reserved.
@@ -34,7 +34,7 @@
 .\" ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 .\" POSSIBILITY OF SUCH DAMAGE.
 .\"
-.Dd July 2, 2007
+.Dd July 4, 2007
 .Dt ENVSTAT 8
 .Os
 .Sh NAME
@@ -110,7 +110,9 @@ section for more information.
 .It Fl s
 Restrict the display to the named sensors.
 The sensor names must be supplied as a comma separated list.
-Sensor names are case sensitive.
+Sensor names are case sensitive. Note that it's mandatory to use the
+.Fl d
+flag to specify the driver that has the sensor.
 .It Fl w
 Use
 .Ar width