diff --git a/packages/babel-cli/bin/babel/index.js b/packages/babel-cli/bin/babel/index.js
index 40d2ddd712..d26c2af9c9 100755
--- a/packages/babel-cli/bin/babel/index.js
+++ b/packages/babel-cli/bin/babel/index.js
@@ -51,7 +51,7 @@ commander.on("--help", function () {
     each(keys(obj).sort(), function (key) {
       if (key[0] === "_") return;
 
-      if (obj[key].metadata.optional) key = "[" + key + "]";
+      if (obj[key].metadata && obj[key].metadata.optional) key = "[" + key + "]";
 
       console.log("    - " + key);
     });