diff --git a/app/code/core/Mage/Checkout/controllers/CartController.php b/app/code/core/Mage/Checkout/controllers/CartController.php
index 36cf66629c009..22100bfde31cf 100644
--- a/app/code/core/Mage/Checkout/controllers/CartController.php
+++ b/app/code/core/Mage/Checkout/controllers/CartController.php
@@ -513,7 +513,7 @@ public function couponPostAction()
             return;
         }
 
-        $couponCode = (string) $this->getRequest()->getParam('coupon_code');
+        $couponCode = trim((string) $this->getRequest()->getParam('coupon_code'));
         if ($this->getRequest()->getParam('remove') == 1) {
             $couponCode = '';
         }