diff --git a/erpnext/accounts/doctype/sales_invoice/sales_invoice.py b/erpnext/accounts/doctype/sales_invoice/sales_invoice.py
index a008742..023f4b0 100644
--- a/erpnext/accounts/doctype/sales_invoice/sales_invoice.py
+++ b/erpnext/accounts/doctype/sales_invoice/sales_invoice.py
@@ -1137,7 +1137,6 @@
 		"""
 		self.set_serial_no_against_delivery_note()
 		self.validate_serial_against_delivery_note()
-		self.validate_serial_against_sales_invoice()
 
 	def set_serial_no_against_delivery_note(self):
 		for item in self.items:
@@ -1168,26 +1167,6 @@
 				frappe.throw(_("Row {0}: {1} Serial numbers required for Item {2}. You have provided {3}.").format(
 					item.idx, item.qty, item.item_code, len(si_serial_nos)))
 
-	def validate_serial_against_sales_invoice(self):
-		""" check if serial number is already used in other sales invoice """
-		for item in self.items:
-			if not item.serial_no:
-				continue
-
-			for serial_no in item.serial_no.split("\n"):
-				serial_no_details = frappe.db.get_value("Serial No", serial_no,
-					["sales_invoice", "item_code"], as_dict=1)
-
-				if not serial_no_details:
-					continue
-
-				if serial_no_details.sales_invoice and serial_no_details.item_code == item.item_code \
-					and self.name != serial_no_details.sales_invoice:
-					sales_invoice_company = frappe.db.get_value("Sales Invoice", serial_no_details.sales_invoice, "company")
-					if sales_invoice_company == self.company:
-						frappe.throw(_("Serial Number: {0} is already referenced in Sales Invoice: {1}")
-							.format(serial_no, serial_no_details.sales_invoice))
-
 	def update_project(self):
 		if self.project:
 			project = frappe.get_doc("Project", self.project)
diff --git a/erpnext/accounts/doctype/sales_invoice/test_sales_invoice.py b/erpnext/accounts/doctype/sales_invoice/test_sales_invoice.py
index 9059d0b..df6d483 100644
--- a/erpnext/accounts/doctype/sales_invoice/test_sales_invoice.py
+++ b/erpnext/accounts/doctype/sales_invoice/test_sales_invoice.py
@@ -933,12 +933,6 @@
 		self.assertFalse(frappe.db.get_value("Serial No", serial_nos[0], "warehouse"))
 		self.assertEqual(frappe.db.get_value("Serial No", serial_nos[0],
 			"delivery_document_no"), si.name)
-		self.assertEqual(frappe.db.get_value("Serial No", serial_nos[0], "sales_invoice"),
-			si.name)
-
-		# check if the serial number is already linked with any other Sales Invoice
-		_si = frappe.copy_doc(si.as_dict())
-		self.assertRaises(frappe.ValidationError, _si.insert)
 
 		return si