diff --git a/composer.json b/composer.json
index d7e330f8..8bbca5e9 100644
--- a/composer.json
+++ b/composer.json
@@ -13,7 +13,7 @@
     ],
     "require": {
         "php": ">=5.3.2",
-        "ext-mongo": ">=1.2.12,<1.6-dev",
+        "ext-mongo": ">=1.2.12,<1.7-dev",
         "doctrine/common": ">=2.1.0,<2.5-dev"
     },
     "autoload": {
diff --git a/lib/Doctrine/MongoDB/Connection.php b/lib/Doctrine/MongoDB/Connection.php
index 32731820..cf15ef0d 100644
--- a/lib/Doctrine/MongoDB/Connection.php
+++ b/lib/Doctrine/MongoDB/Connection.php
@@ -143,7 +143,12 @@ public function isConnected()
             return false;
         }
 
-        return $this->mongo->connected;
+        /* MongoClient::$connected is deprecated in 1.5.0+, so count the list of
+         * connected hosts instead.
+         */
+        return version_compare(phpversion('mongo'), '1.5.0', '<')
+            ? $this->mongo->connected
+            : count($this->mongo->getHosts()) > 0;
     }
 
     /**
diff --git a/tests/Doctrine/MongoDB/Tests/ConnectionFunctionalTest.php b/tests/Doctrine/MongoDB/Tests/ConnectionFunctionalTest.php
new file mode 100644
index 00000000..c1704dfc
--- /dev/null
+++ b/tests/Doctrine/MongoDB/Tests/ConnectionFunctionalTest.php
@@ -0,0 +1,15 @@
+<?php
+
+namespace Doctrine\MongoDB\Tests;
+
+class ConnectionFunctionalTest extends BaseTest
+{
+    public function testIsConnected()
+    {
+        $this->assertFalse($this->conn->isConnected());
+        $this->conn->connect();
+        $this->assertTrue($this->conn->isConnected());
+        $this->conn->close();
+        $this->assertFalse($this->conn->isConnected());
+    }
+}