diff --git a/src/Symfony/Component/HttpFoundation/Session/Storage/Handler/MongoDbSessionHandler.php b/src/Symfony/Component/HttpFoundation/Session/Storage/Handler/MongoDbSessionHandler.php
index 2315bf8f58..5289b5c258 100644
--- a/src/Symfony/Component/HttpFoundation/Session/Storage/Handler/MongoDbSessionHandler.php
+++ b/src/Symfony/Component/HttpFoundation/Session/Storage/Handler/MongoDbSessionHandler.php
@@ -36,13 +36,18 @@ class MongoDbSessionHandler implements \SessionHandlerInterface
     /**
      * Constructor.
      *
-     * @param \Mongo $mongo   A "Mongo" instance
+     * @param object $mongo   A MongoClient or Mongo instance
      * @param array  $options An associative array of field options
      *
+     * @throws \InvalidArgumentException When MongoClient or Mongo instance not provided
      * @throws \InvalidArgumentException When "database" or "collection" not provided
      */
-    public function __construct(\Mongo $mongo, array $options)
+    public function __construct($mongo, array $options)
     {
+        if (!($mongo instanceof \MongoClient || $mongo instanceof \Mongo)) {
+            throw new \InvalidArgumentException('MongoClient or Mongo instance required');
+        }
+
         if (!isset($options['database']) || !isset($options['collection'])) {
             throw new \InvalidArgumentException('You must provide the "database" and "collection" option for MongoDBSessionHandler');
         }
diff --git a/src/Symfony/Component/HttpFoundation/Tests/Session/Storage/Handler/MongoDbSessionHandlerTest.php b/src/Symfony/Component/HttpFoundation/Tests/Session/Storage/Handler/MongoDbSessionHandlerTest.php
index f7e51d87e1..04d3a3f171 100644
--- a/src/Symfony/Component/HttpFoundation/Tests/Session/Storage/Handler/MongoDbSessionHandlerTest.php
+++ b/src/Symfony/Component/HttpFoundation/Tests/Session/Storage/Handler/MongoDbSessionHandlerTest.php
@@ -27,11 +27,13 @@ class MongoDbSessionHandlerTest extends \PHPUnit_Framework_TestCase
 
     protected function setUp()
     {
-        if (!class_exists('\Mongo')) {
-            $this->markTestSkipped('MongoDbSessionHandler requires the php "mongo" extension');
+        if (!extension_loaded('mongo')) {
+            $this->markTestSkipped('MongoDbSessionHandler requires the PHP "mongo" extension.');
         }
 
-        $this->mongo = $this->getMockBuilder('Mongo')
+        $mongoClass = (version_compare(phpversion('mongo'), '1.3.0', '<')) ? 'Mongo' : 'MongoClient';
+
+        $this->mongo = $this->getMockBuilder($mongoClass)
             ->disableOriginalConstructor()
             ->getMock();
 
@@ -46,6 +48,22 @@ class MongoDbSessionHandlerTest extends \PHPUnit_Framework_TestCase
         $this->storage = new MongoDbSessionHandler($this->mongo, $this->options);
     }
 
+    /**
+     * @expectedException InvalidArgumentException
+     */
+    public function testConstructorShouldThrowExceptionForInvalidMongo()
+    {
+        new MongoDbSessionHandler(new \stdClass(), $this->options);
+    }
+
+    /**
+     * @expectedException InvalidArgumentException
+     */
+    public function testConstructorShouldThrowExceptionForMissingOptions()
+    {
+        new MongoDbSessionHandler($this->mongo, array());
+    }
+
     public function testOpenMethodAlwaysReturnTrue()
     {
         $this->assertTrue($this->storage->open('test', 'test'), 'The "open" method should always return true');