diff --git a/erpnext/accounts/doctype/sales_invoice/sales_invoice.py b/erpnext/accounts/doctype/sales_invoice/sales_invoice.py
index ae253cc2f3a..20b5fb391e2 100644
--- a/erpnext/accounts/doctype/sales_invoice/sales_invoice.py
+++ b/erpnext/accounts/doctype/sales_invoice/sales_invoice.py
@@ -501,12 +501,15 @@ class SalesInvoice(SellingController):
 
 	def so_dn_required(self):
 		"""check in manage account if sales order / delivery note required or not."""
+		if self.is_return:
+			return
 		dic = {'Sales Order':['so_required', 'is_pos'],'Delivery Note':['dn_required', 'update_stock']}
 		for i in dic:
 			if frappe.db.get_single_value('Selling Settings', dic[i][0]) == 'Yes':
 				for d in self.get('items'):
-					if (d.item_code and frappe.get_cached_value('Item', d.item_code, 'is_stock_item') == 1
-						and not d.get(i.lower().replace(' ','_')) and not self.get(dic[i][1])):
+					is_stock_item = frappe.get_cached_value('Item', d.item_code, 'is_stock_item')
+					if d.item_code and is_stock_item == 1\
+						and not d.get(i.lower().replace(' ','_')) and not self.get(dic[i][1]):
 						msgprint(_("{0} is mandatory for Item {1}").format(i,d.item_code), raise_exception=1)