diff --git a/usr.sbin/sendmail/mailstats/mailstats.c b/usr.sbin/sendmail/mailstats/mailstats.c
index 97ec33be7e92..a3015b854789 100644
--- a/usr.sbin/sendmail/mailstats/mailstats.c
+++ b/usr.sbin/sendmail/mailstats/mailstats.c
@@ -91,7 +91,7 @@ main(argc, argv)
 		  case '?':
 		  default:
   usage:
-			fputs("usage: mailstats [-C cffile] [-f stfile]\n", stderr);
+			fputs("usage: mailstats [-o] [-C cffile] [-f stfile]\n", stderr);
 			exit(EX_USAGE);
 		}
 	}