diff --git a/admin-dev/pdf.php b/admin-dev/pdf.php
index 699818792..cacbe7dd8 100644
--- a/admin-dev/pdf.php
+++ b/admin-dev/pdf.php
@@ -146,7 +146,7 @@ function generateDeliverySlipPDFByIdOrderInvoice($id_order_invoice)
 
 function generateInvoicesPDF()
 {
-	$order_invoice_collection = OrderInvoice::getByDateInterval($_GET['date_from'], $_GET['date_to'], NULL, 'invoice');
+	$order_invoice_collection = OrderInvoice::getByDateInterval($_GET['date_from'], $_GET['date_to']);
 
 	if (!sizeof($order_invoice_collection))
 		die(Tools::displayError('No invoices found'));
@@ -182,9 +182,12 @@ function generateOrderSlipsPDF()
 
 function generateDeliverySlipsPDF()
 {
-	$slips = unserialize(urldecode($_GET['deliveryslips']));
-	if (is_array($slips))
-		generatePDF($slips, PDF::TEMPLATE_DELIVERY_SLIP);
+	$order_invoice_collection = OrderInvoice::getByDeliveryDateInterval(Tools::getValue('date_from'), Tools::getValue('date_to'));
+
+	if (!sizeof($order_invoice_collection))
+		die(Tools::displayError('No invoices found'));
+
+	generatePDF($order_invoice_collection, PDF::TEMPLATE_DELIVERY_SLIP);
 }
 
 function generatePDF($object, $template)
diff --git a/classes/order/Order.php b/classes/order/Order.php
index f5d5e80a2..d81287be6 100644
--- a/classes/order/Order.php
+++ b/classes/order/Order.php
@@ -851,17 +851,17 @@ class OrderCore extends ObjectModel
 		return Db::getInstance(_PS_USE_SQL_SLAVE_)->executeS($sql);
 	}
 
-    /**
-     * @deprecated since 1.5.0.2
-     *
-     * @static
-     * @param $date_from
-     * @param $date_to
-     * @param $id_customer
-     * @param $type
-     *
-     * @return array
-     */
+	/**
+	 * @deprecated since 1.5.0.2
+	 *
+	 * @static
+	 * @param $date_from
+	 * @param $date_to
+	 * @param $id_customer
+	 * @param $type
+	 *
+	 * @return array
+	 */
 	public static function getOrdersIdInvoiceByDate($date_from, $date_to, $id_customer = NULL, $type = NULL)
 	{
         Tools::displayAsDeprecated();
diff --git a/classes/order/OrderInvoice.php b/classes/order/OrderInvoice.php
index c34e92ae5..96231df74 100644
--- a/classes/order/OrderInvoice.php
+++ b/classes/order/OrderInvoice.php
@@ -422,8 +422,8 @@ class OrderInvoiceCore extends ObjectModel
 			LEFT JOIN `'._DB_PREFIX_.'orders` o ON (o.`id_order` = oi.`id_order`)
 			WHERE DATE_ADD(oi.date_add, INTERVAL -1 DAY) <= \''.pSQL($date_to).'\'
 			AND oi.date_add >= \''.pSQL($date_from).'\'
-			'.Context::getContext()->shop->addSqlRestriction().
-			' ORDER BY oi.date_add ASC
+			'.Context::getContext()->shop->addSqlRestriction().'
+			ORDER BY oi.date_add ASC
 		');
 
 		return ObjectModel::hydrateCollection('OrderInvoice', $order_invoice_list);
@@ -455,6 +455,28 @@ class OrderInvoiceCore extends ObjectModel
 		return ObjectModel::hydrateCollection('OrderInvoice', $order_invoice_list);
 	}
 
+	/**
+	 * @since 1.5.0.3
+	 * @static
+	 * @param $date_from
+	 * @param $date_to
+	 * @return array collection of invoice
+	 */
+	public static function getByDeliveryDateInterval($date_from, $date_to)
+	{
+		$order_invoice_list = Db::getInstance()->ExecuteS('
+			SELECT oi.*
+			FROM `'._DB_PREFIX_.'order_invoice` oi
+			LEFT JOIN `'._DB_PREFIX_.'orders` o ON (o.`id_order` = oi.`id_order`)
+			WHERE DATE_ADD(oi.delivery_date, INTERVAL -1 DAY) <= \''.pSQL($date_to).'\'
+			AND oi.date_add >= \''.pSQL($date_from).'\'
+			'.Context::getContext()->shop->addSqlRestriction().'
+			ORDER BY oi.delivery_date ASC
+		');
+
+		return ObjectModel::hydrateCollection('OrderInvoice', $order_invoice_list);
+	}
+
 	/**
 	 * @since 1.5
 	 * @static
diff --git a/controllers/admin/AdminDeliverySlipController.php b/controllers/admin/AdminDeliverySlipController.php
index 27adaa325..13cdf66de 100644
--- a/controllers/admin/AdminDeliverySlipController.php
+++ b/controllers/admin/AdminDeliverySlipController.php
@@ -108,9 +108,8 @@ class AdminDeliverySlipControllerCore extends AdminController
 				$this->_errors[] = Tools::displayError('Invalid end date');
 			if (!count($this->_errors))
 			{
-				$orders = Order::getOrdersIdByDate(Tools::getValue('date_from'), Tools::getValue('date_to'), null, 'delivery');
-				if (count($orders))
-					Tools::redirectAdmin('pdf.php?deliveryslips='.urlencode(serialize($orders)).'&token='.$this->token);
+				if (count(OrderInvoice::getByDeliveryDateInterval(Tools::getValue('date_from'), Tools::getValue('date_to'))))
+					Tools::redirectAdmin('pdf.php?deliveryslips&date_from='.urlencode(Tools::getValue('date_from')).'&date_to='.urlencode(Tools::getValue('date_to')).'&token='.$this->token);
 				else
 					$this->_errors[] = Tools::displayError('No delivery slip found for this period');
 			}
diff --git a/controllers/admin/AdminInvoicesController.php b/controllers/admin/AdminInvoicesController.php
index 85ac6af68..a30f9a56c 100644
--- a/controllers/admin/AdminInvoicesController.php
+++ b/controllers/admin/AdminInvoicesController.php
@@ -217,9 +217,7 @@ class AdminInvoicesControllerCore extends AdminController
 
 			if (!count($this->_errors))
 			{
-				$order_invoice_list = OrderInvoice::getByDateInterval(Tools::getValue('date_from'), Tools::getValue('date_to'));
-
-				if (count($order_invoice_list))
+				if (count(OrderInvoice::getByDateInterval(Tools::getValue('date_from'), Tools::getValue('date_to'))))
 					Tools::redirectAdmin('pdf.php?invoices&date_from='.urlencode(Tools::getValue('date_from')).'&date_to='.urlencode(Tools::getValue('date_to')).'&token='.$this->token);
 
 				$this->_errors[] = $this->l('No invoice found for this period');
@@ -232,7 +230,7 @@ class AdminInvoicesControllerCore extends AdminController
 			else
 			{
 				foreach ($status_array as $id_order_state)
-					if (count($orders = Order::getOrderIdsByStatus((int)$id_order_state)))
+					if (count(OrderInvoice::getByStatus((int)$id_order_state)))
 						Tools::redirectAdmin('pdf.php?invoices2&id_order_state='.implode('-', $status_array).'&token='.$this->token);
 
 				$this->_errors[] = $this->l('No invoice found for this status');