diff --git a/usr.sbin/arp/arp.c b/usr.sbin/arp/arp.c
index 8bdd555aebd3..25fbb23b36fc 100644
--- a/usr.sbin/arp/arp.c
+++ b/usr.sbin/arp/arp.c
@@ -187,8 +187,11 @@ main(int argc, char *argv[])
 			if (argc != 0)
 				usage();
 			search(0, nuke_entry);
-		} else
+		} else {
+			if (argc != 1)
+				usage();
 			rtn = delete(argv[0]);
+		}
 		break;
 	case F_FILESET:
 		if (argc != 1)