diff --git a/apps/aomenc.c b/apps/aomenc.c
index 11035bf..da3b914 100644
--- a/apps/aomenc.c
+++ b/apps/aomenc.c
@@ -681,6 +681,8 @@
 
   if (global->usage == AOM_USAGE_REALTIME && global->passes > 1) {
     warn("Enforcing one-pass encoding in realtime mode\n");
+    if (global->pass > 1)
+      die("Error: Invalid --pass=%d for one-pass encoding\n", global->pass);
     global->passes = 1;
   }