diff --git a/erpnext/selling/doctype/sales_order/sales_order.py b/erpnext/selling/doctype/sales_order/sales_order.py
index e12b359..e97a4ee 100755
--- a/erpnext/selling/doctype/sales_order/sales_order.py
+++ b/erpnext/selling/doctype/sales_order/sales_order.py
@@ -834,6 +834,10 @@
 		for item in sales_order.items:
 			if item.supplier and item.supplier not in suppliers:
 				suppliers.append(item.supplier)
+
+	if not suppliers:
+		frappe.throw(_("Please set a Supplier against the Items to be considered in the Purchase Order."))
+
 	for supplier in suppliers:
 		po =frappe.get_list("Purchase Order", filters={"sales_order":source_name, "supplier":supplier, "docstatus": ("<", "2")})
 		if len(po) == 0: