diff --git a/classes/Validate.php b/classes/Validate.php
index 01ee11fd1..a3083572d 100644
--- a/classes/Validate.php
+++ b/classes/Validate.php
@@ -1067,4 +1067,9 @@ class ValidateCore
 	{
 		return (preg_match('/^[0-1]\.[0-9]{1,2}(\.[0-9]{1,2}){0,2}$/', $version) && ip2long($version));
 	}
+
+	public static function isOrderInvoiceNumber($id)
+	{
+		return (preg_match('/^['.Configuration::get('PS_INVOICE_PREFIX', Context::getContext()->language->id).']*([0-9]+)?/i', $id));
+	}
 }
\ No newline at end of file
diff --git a/classes/order/OrderInvoice.php b/classes/order/OrderInvoice.php
index 97152e37a..8271c9477 100644
--- a/classes/order/OrderInvoice.php
+++ b/classes/order/OrderInvoice.php
@@ -123,6 +123,28 @@ class OrderInvoiceCore extends ObjectModel
 		AND od.`id_order_invoice` = '.(int)$this->id);
 	}
 
+	public static function getInvoiceByNumber($id_invoice)
+	{
+		if (is_numeric($id_invoice))
+			$id_invoice = (int)($id_invoice);
+		elseif (is_string($id_invoice))
+		{
+			$matches = array();
+			if (preg_match('/^['.Configuration::get('PS_INVOICE_PREFIX', Context::getContext()->language->id).']*([0-9]+)?/i', $id_invoice, $matches) !== FALSE)
+				$id_invoice = $matches[1];
+		}
+		else
+			return false;
+
+		$id_order_invoice = Db::getInstance(_PS_USE_SQL_SLAVE_)->getValue('
+			SELECT `id_order_invoice`
+			FROM `'._DB_PREFIX_.'order_invoice`
+			WHERE number = '.$id_invoice
+		);
+
+		return ($id_order_invoice ? new OrderInvoice($id_order_invoice) : false);
+	}
+
 	/**
 	 * Get order products
 	 *
diff --git a/controllers/admin/AdminSearchController.php b/controllers/admin/AdminSearchController.php
index 0a400c1d8..7b7bea3c0 100644
--- a/controllers/admin/AdminSearchController.php
+++ b/controllers/admin/AdminSearchController.php
@@ -124,8 +124,8 @@ class AdminSearchControllerCore extends AdminController
 			/* Invoices */
 			if ($searchType == 4)
 			{
-				if ((int)$this->query && Validate::isUnsignedInt((int)$this->query) && ($invoice = Order::getInvoice((int)$this->query)))
-					Tools::redirectAdmin($this->context->link->getAdminLink('AdminPdf').'&submitAction=generateInvoicePDF&id_order='.(int)($invoice['id_order']));
+				if (Validate::isOrderInvoiceNumber($this->query) && ($invoice = OrderInvoice::getInvoiceByNumber($this->query)))
+					Tools::redirectAdmin($this->context->link->getAdminLink('AdminPdf').'&submitAction=generateInvoicePDF&id_order='.(int)($invoice->id_order));
 				$this->errors[] = Tools::displayError('No invoice was found with this ID:').' '.Tools::htmlentitiesUTF8($this->query);
 			}