diff --git a/lib/output.js b/lib/output.js
index 1a1a8216..48ed25a3 100644
--- a/lib/output.js
+++ b/lib/output.js
@@ -87,6 +87,8 @@ function OutputStream(options) {
         ecma             : 5,
         wrap_iife        : false,
     }, true);
+    if (typeof options.ascii_identifiers === 'undefined')
+        options.ascii_identifiers = options.ascii_only;
 
     if (typeof options.ascii_identifiers === 'undefined')
         options.ascii_identifiers = options.ascii_only;