diff --git a/src/Elasticsearch/Endpoints/Cat/Aliases.php b/src/Elasticsearch/Endpoints/Cat/Aliases.php
index 9f5e47738..7ed256caf 100644
--- a/src/Elasticsearch/Endpoints/Cat/Aliases.php
+++ b/src/Elasticsearch/Endpoints/Cat/Aliases.php
@@ -60,6 +60,7 @@ protected function getParamWhitelist()
             'h',
             'help',
             'v',
+            'format'
         );
     }