diff --git a/erpnext/selling/doctype/sales_order/sales_order.py b/erpnext/selling/doctype/sales_order/sales_order.py
index bff3ee52ffe..3e58b91b558 100755
--- a/erpnext/selling/doctype/sales_order/sales_order.py
+++ b/erpnext/selling/doctype/sales_order/sales_order.py
@@ -547,9 +547,7 @@ class SalesOrder(SellingController):
 
 		for item in self.items:
 			if item.supplier:
-				supplier = frappe.db.get_value(
-					"Sales Order Item", {"parent": self.name, "item_code": item.item_code}, "supplier"
-				)
+				supplier = frappe.db.get_value("Sales Order Item", item.name, "supplier")
 				if item.ordered_qty > 0.0 and item.supplier != supplier:
 					exc_list.append(
 						_("Row #{0}: Not allowed to change Supplier as Purchase Order already exists").format(