diff --git a/lib/index.js b/lib/index.js
index 21954ec..bd9122d 100644
--- a/lib/index.js
+++ b/lib/index.js
@@ -26,7 +26,7 @@ function authorize(options) {
   };
 
   var auth = xtend({}, defaults, options );
-  
+
   auth.userProperty = auth.passport._userProperty || 'user';
 
   if (typeof auth.cookieParser === 'undefined' || !auth.cookieParser) {
@@ -55,10 +55,11 @@ function authorize(options) {
 
       var userKey = session[ auth.passport._key ][ auth.userProperty ];
 
-      if( !userKey && auth.fail ) {
-        return auth.fail( data, accept );
-      } else if( !userKey ) {
-        return accept(null, false);
+      if(userKey === undefined)
+        if(auth.fail)
+          return auth.fail( data, accept );
+        else
+          return accept(null, false);
       }
 
       auth.passport.deserializeUser(userKey, function(err, user) {