diff --git a/classes/order/OrderPayment.php b/classes/order/OrderPayment.php
index fc0d93455..412d6b796 100644
--- a/classes/order/OrderPayment.php
+++ b/classes/order/OrderPayment.php
@@ -48,7 +48,7 @@ class OrderPaymentCore extends ObjectModel
 		'fields' => array(
 			'order_reference' => 	array('type' => self::TYPE_STRING, 'validate' => 'isAnything', 'size' => 9),
 			'id_currency' => 		array('type' => self::TYPE_INT, 'validate' => 'isUnsignedId', 'required' => true),
-			'amount' => 			array('type' => self::TYPE_FLOAT, 'validate' => 'isPrice', 'required' => true),
+			'amount' => 			array('type' => self::TYPE_FLOAT, 'validate' => 'isNegativePrice', 'required' => true),
 			'payment_method' => 	array('type' => self::TYPE_STRING, 'validate' => 'isGenericName'),
 			'conversion_rate' => 	array('type' => self::TYPE_INT, 'validate' => 'isFloat'),
 			'transaction_id' => 	array('type' => self::TYPE_STRING, 'validate' => 'isAnything', 'size' => 254),
diff --git a/controllers/admin/AdminOrdersController.php b/controllers/admin/AdminOrdersController.php
index 48187c713..667cfdcdb 100755
--- a/controllers/admin/AdminOrdersController.php
+++ b/controllers/admin/AdminOrdersController.php
@@ -819,7 +819,7 @@ class AdminOrdersControllerCore extends AdminController
 
 				if (!Validate::isLoadedObject($order))
 					$this->errors[] = Tools::displayError('Order can\'t be found');
-				elseif (!Validate::isPrice($amount))
+				elseif (!Validate::isNegativePrice($amount))
 					$this->errors[] = Tools::displayError('Amount is invalid');
 				elseif (!Validate::isString(Tools::getValue('payment_method')))
 					$this->errors[] = Tools::displayError('Payment method is invalid');