diff --git a/plugins/ntpdate b/plugins/ntpdate
index 2da8b33..639d898 100644
--- a/plugins/ntpdate
+++ b/plugins/ntpdate
@@ -1,6 +1,7 @@
 config_ntpdate() {
   echo "graph_title NTP offset and dealy to peer $NTP_PEER"
   echo "graph_args --base 1000 --vertical-label msec"
+  echo "graph_category time"
   echo "offset.label Offset"
   echo "offset.draw LINE2"
   echo "delay.label Delay"