diff --git a/accounts/doctype/sales_invoice/sales_invoice.py b/accounts/doctype/sales_invoice/sales_invoice.py
index c17654a..956867d 100644
--- a/accounts/doctype/sales_invoice/sales_invoice.py
+++ b/accounts/doctype/sales_invoice/sales_invoice.py
@@ -149,7 +149,7 @@
 				ret = get_obj('Sales Common').get_item_details(item.fields, self)
 				for fieldname, value in ret.items():
 					if self.meta.get_field(fieldname, parentfield="entries") and \
-						not item.fields.get(fieldname):
+						item.fields.get(fieldname) is None:
 							item.fields[fieldname] = value
 		
 		# fetch pos details, if they are not fetched