diff --git a/classes/Category.php b/classes/Category.php
index 0ba3501f4..3a806eae3 100644
--- a/classes/Category.php
+++ b/classes/Category.php
@@ -1277,7 +1277,7 @@ class CategoryCore extends ObjectModel
 		'.$sql);
 	}
 
-	public function getRootCategories($id_lang = null, $active = true)
+	public static function getRootCategories($id_lang = null, $active = true)
 	{
 		if (!$id_lang)
 			$id_lang = Context::getContext()->language->id;