diff --git a/erpnext/controllers/selling_controller.py b/erpnext/controllers/selling_controller.py
index 2cbe596..52d58dc 100644
--- a/erpnext/controllers/selling_controller.py
+++ b/erpnext/controllers/selling_controller.py
@@ -45,6 +45,7 @@
 		self.set_gross_profit()
 		set_default_income_account_for_item(self)
 		self.set_customer_address()
+		self.validate_for_duplicate_items()
 
 	def set_missing_values(self, for_validate=False):
 
@@ -381,6 +382,34 @@
 			if self.get(address_field):
 				self.set(address_display_field, get_address_display(self.get(address_field)))
 
+	def validate_for_duplicate_items(self):
+		check_list, chk_dupl_itm = [], []
+		if cint(frappe.db.get_single_value("Selling Settings", "allow_multiple_items")):
+			return
+
+		for d in self.get('items'):
+			if self.doctype == "Sales Invoice":
+				e = [d.item_code, d.description, d.warehouse, d.sales_order or d.delivery_note, d.batch_no or '']
+				f = [d.item_code, d.description, d.sales_order or d.delivery_note]
+			elif self.doctype == "Delivery Note":
+				e = [d.item_code, d.description, d.warehouse, d.against_sales_order or d.against_sales_invoice, d.batch_no or '']
+				f = [d.item_code, d.description, d.against_sales_order or d.against_sales_invoice]
+			elif self.doctype == "Sales Order":
+				e = [d.item_code, d.description, d.warehouse, d.batch_no or '']
+				f = [d.item_code, d.description]
+
+			if frappe.db.get_value("Item", d.item_code, "is_stock_item") == 1:
+				if e in check_list:
+					frappe.throw(_("Note: Item {0} entered multiple times").format(d.item_code))
+				else:
+					check_list.append(e)
+			else:
+				if f in chk_dupl_itm:
+					frappe.throw(_("Note: Item {0} entered multiple times").format(d.item_code))
+				else:
+					chk_dupl_itm.append(f)
+
+
 	def validate_items(self):
 		# validate items to see if they have is_sales_item enabled
 		from erpnext.controllers.buying_controller import validate_item_type
diff --git a/erpnext/selling/doctype/sales_order/sales_order.py b/erpnext/selling/doctype/sales_order/sales_order.py
index 09dc9a9..4342af5 100755
--- a/erpnext/selling/doctype/sales_order/sales_order.py
+++ b/erpnext/selling/doctype/sales_order/sales_order.py
@@ -72,9 +72,7 @@
 				frappe.msgprint(_("Warning: Sales Order {0} already exists against Customer's Purchase Order {1}").format(so[0][0], self.po_no))
 
 	def validate_for_items(self):
-		check_list = []
 		for d in self.get('items'):
-			check_list.append(cstr(d.item_code))
 
 			# used for production plan
 			d.transaction_date = self.transaction_date
@@ -83,13 +81,6 @@
 				where item_code = %s and warehouse = %s", (d.item_code, d.warehouse))
 			d.projected_qty = tot_avail_qty and flt(tot_avail_qty[0][0]) or 0
 
-		# check for same entry multiple times
-		unique_chk_list = set(check_list)
-		if len(unique_chk_list) != len(check_list) and \
-			not cint(frappe.db.get_single_value("Selling Settings", "allow_multiple_items")):
-			frappe.msgprint(_("Same item has been entered multiple times"),
-				title=_("Warning"), indicator='orange')
-
 	def product_bundle_has_stock_item(self, product_bundle):
 		"""Returns true if product bundle has stock item"""
 		ret = len(frappe.db.sql("""select i.name from tabItem i, `tabProduct Bundle Item` pbi
diff --git a/erpnext/stock/doctype/delivery_note/delivery_note.py b/erpnext/stock/doctype/delivery_note/delivery_note.py
index 2de9b97..f79d127 100644
--- a/erpnext/stock/doctype/delivery_note/delivery_note.py
+++ b/erpnext/stock/doctype/delivery_note/delivery_note.py
@@ -166,24 +166,7 @@
 				frappe.throw(_("Customer {0} does not belong to project {1}").format(self.customer, self.project))
 
 	def validate_for_items(self):
-		check_list, chk_dupl_itm = [], []
-		if cint(frappe.db.get_single_value("Selling Settings", "allow_multiple_items")):
-			return
-
 		for d in self.get('items'):
-			e = [d.item_code, d.description, d.warehouse, d.against_sales_order or d.against_sales_invoice, d.batch_no or '']
-			f = [d.item_code, d.description, d.against_sales_order or d.against_sales_invoice]
-
-			if frappe.db.get_value("Item", d.item_code, "is_stock_item") == 1:
-				if e in check_list:
-					frappe.msgprint(_("Note: Item {0} entered multiple times").format(d.item_code))
-				else:
-					check_list.append(e)
-			else:
-				if f in chk_dupl_itm:
-					frappe.msgprint(_("Note: Item {0} entered multiple times").format(d.item_code))
-				else:
-					chk_dupl_itm.append(f)
 			#Customer Provided parts will have zero valuation rate
 			if frappe.db.get_value('Item', d.item_code, 'is_customer_provided_item'):
 				d.allow_zero_valuation_rate = 1