diff --git a/lib/url_parser.js b/lib/url_parser.js
index dfa1aa0be6..3f931fe8bc 100644
--- a/lib/url_parser.js
+++ b/lib/url_parser.js
@@ -10,9 +10,8 @@ var ReadPreference = require('./read_preference'),
 module.exports = function(url, options, callback) {
   var result = parser.parse(url, true);
   if (result.protocol !== 'mongodb:') {
-    // TODO fix this
     if (result.protocol !== 'mongodb+srv:') {
-      throw new Error('invalid schema, expected mongodb or mongodb+srv');
+      callback(new Error('invalid schema, expected mongodb or mongodb+srv'));
     }
   }