diff --git a/index.php b/index.php
index 09281fd3dee34c4a4ef9681ed8d3a72b6d163c68..e3486c3e3fee63ad4ade27b77b4c0f600e6da72c 100644
--- a/index.php
+++ b/index.php
@@ -32,6 +32,7 @@ require_once PIWIK_INCLUDE_PATH . '/core/testMinimumPhpVersion.php';
 
 session_cache_limiter('nocache');
 @date_default_timezone_set('UTC');
+require_once PIWIK_INCLUDE_PATH . '/vendor/autoload.php';
 require_once PIWIK_INCLUDE_PATH . '/core/Loader.php';
 
 if (!defined('PIWIK_ENABLE_ERROR_HANDLER') || PIWIK_ENABLE_ERROR_HANDLER) {