diff --git a/src/Redsys/Tpv/Tpv.php b/src/Redsys/Tpv/Tpv.php
index d0bd3ca..2e72422 100644
--- a/src/Redsys/Tpv/Tpv.php
+++ b/src/Redsys/Tpv/Tpv.php
@@ -263,7 +263,7 @@ private function setValue(array $options, $option)
     public function getOrder($order)
     {
         if (preg_match('/^[0-9]+$/', $order)) {
-            $order = sprintf('%012d', $order);
+            $order = sprintf('%012s', $order);
         }
 
         $len = strlen($order);