diff --git a/erpnext/manufacturing/doctype/production_order/production_order.py b/erpnext/manufacturing/doctype/production_order/production_order.py
index 2bf3204..250d6e6 100644
--- a/erpnext/manufacturing/doctype/production_order/production_order.py
+++ b/erpnext/manufacturing/doctype/production_order/production_order.py
@@ -55,7 +55,8 @@
 				if not self.expected_delivery_date:
 					self.expected_delivery_date = so[0].delivery_date
 
-				self.project = so[0].project
+				if so[0].project:
+					self.project = so[0].project
 
 				self.validate_production_order_against_so()
 			else: