diff --git a/src/Composer/Repository/ComposerRepository.php b/src/Composer/Repository/ComposerRepository.php
index 9bdd9f05d..f7e021e3e 100644
--- a/src/Composer/Repository/ComposerRepository.php
+++ b/src/Composer/Repository/ComposerRepository.php
@@ -70,7 +70,7 @@ class ComposerRepository extends ArrayRepository implements NotifiableRepository
             array(
                 'method'  => 'POST',
                 'header'  => 'Content-type: application/x-www-form-urlencoded',
-                'content' => http_build_query($params),
+                'content' => http_build_query($params, '', '&'),
                 'timeout' => 3,
             )
         );