diff --git a/lib/passport/middleware/authenticate.js b/lib/passport/middleware/authenticate.js
index <HASH>..<HASH> 100644
--- a/lib/passport/middleware/authenticate.js
+++ b/lib/passport/middleware/authenticate.js
@@ -54,7 +54,7 @@ var http = require('http')
  * @api public
  */
 module.exports = function authenticate(name, options, callback) {
-  if (!callback && typeof options === 'function') {
+  if (typeof options == 'function') {
     callback = options;
     options = {};
   }
Simplify polymorphic check.