diff --git a/erpnext/stock/doctype/item/item.py b/erpnext/stock/doctype/item/item.py
index e2e84c4..7d31942 100644
--- a/erpnext/stock/doctype/item/item.py
+++ b/erpnext/stock/doctype/item/item.py
@@ -101,6 +101,7 @@
 		self.add_default_uom_in_conversion_factor_table()
 		self.validate_conversion_factor()
 		self.validate_item_type()
+		self.validate_naming_series()
 		self.check_for_active_boms()
 		self.fill_customer_code()
 		self.check_item_tax()
@@ -186,7 +187,7 @@
 					or frappe.db.get_single_value('Stock Settings', 'default_warehouse'))
 			if default_warehouse:
 				warehouse_company = frappe.db.get_value("Warehouse", default_warehouse, "company")
-			
+
 			if not default_warehouse or warehouse_company != default.company:
 				default_warehouse = frappe.db.get_value('Warehouse',
 					{'warehouse_name': _('Stores'), 'company': default.company})
@@ -522,6 +523,13 @@
 		if self.has_serial_no == 0 and self.serial_no_series:
 			self.serial_no_series = None
 
+	def validate_naming_series(self):
+		for field in ["serial_no_series", "batch_number_series"]:
+			series = self.get(field)
+			if series and "#" in series and "." not in series:
+				frappe.throw(_("Invalid naming series (. missing) for {0}")
+					.format(frappe.bold(self.meta.get_field(field).label)))
+
 	def check_for_active_boms(self):
 		if self.default_bom:
 			bom_item = frappe.db.get_value("BOM", self.default_bom, "item")
@@ -1007,8 +1015,6 @@
 		order by pr.posting_date desc, pr.posting_time desc, pr.name desc
 		limit 1""", (item_code, cstr(doc_name)), as_dict=1)
 
-	
-	
 	purchase_order_date = getdate(last_purchase_order and last_purchase_order[0].transaction_date
 							   or "1900-01-01")
 	purchase_receipt_date = getdate(last_purchase_receipt and
@@ -1016,7 +1022,7 @@
 
 	if last_purchase_order and (purchase_order_date >= purchase_receipt_date or not last_purchase_receipt):
 		# use purchase order
-		
+
 		last_purchase = last_purchase_order[0]
 		purchase_date = purchase_order_date
 
@@ -1036,7 +1042,7 @@
 		"discount_percentage": flt(last_purchase.discount_percentage),
 		"purchase_date": purchase_date
 	})
-	
+
 
 	conversion_rate = flt(conversion_rate) or 1.0
 	out.update({