diff --git a/erpnext/stock/doctype/serial_no/serial_no.py b/erpnext/stock/doctype/serial_no/serial_no.py
index 71ce0f8..485f90f 100644
--- a/erpnext/stock/doctype/serial_no/serial_no.py
+++ b/erpnext/stock/doctype/serial_no/serial_no.py
@@ -159,13 +159,19 @@
 
 	def after_rename(self, old, new, merge=False):
 		"""rename serial_no text fields"""
+		print "--------------------RENAME SERIAL NO-------------------------------"		
+		print old
+		print new
 		for dt in frappe.db.sql("""select parent from tabDocField
 			where fieldname='serial_no' and fieldtype='Text'"""):
-
+			print "--------------GOT PARENTS-------------------"
 			for item in frappe.db.sql("""select name, serial_no from `tab%s`
 				where serial_no like '%%%s%%'""" % (dt[0], frappe.db.escape(old))):
 
-				serial_nos = map(lambda i: i==old and new or i, item[1].split('\n'))
+				serial_nos = map(lambda i: new if i.upper()==old.upper() else i, item[1].split('\n'))
+				print "----------------------IN SERIAL NO-------------------------------"
+				print serial_nos
+				print "-----------------------------------------------------------------"
 				frappe.db.sql("""update `tab%s` set serial_no = %s
 					where name=%s""" % (dt[0], '%s', '%s'),
 					('\n'.join(serial_nos), item[0]))