diff --git a/lib/Gitlab/Api/Projects.php b/lib/Gitlab/Api/Projects.php
index f5f67df16..fb8621066 100644
--- a/lib/Gitlab/Api/Projects.php
+++ b/lib/Gitlab/Api/Projects.php
@@ -84,7 +84,7 @@ public function all(array $parameters = [])
     }
 
     /**
-     * @param int $project_id
+     * @param int|string $project_id
      * @param array $parameters {
      *
      *     @var bool   $statistics                    Include project statistics.