diff --git a/frappe/app.py b/frappe/app.py
index 822c061b67..76018e391e 100644
--- a/frappe/app.py
+++ b/frappe/app.py
@@ -5,6 +5,7 @@ from __future__ import unicode_literals
 import sys, os
 import json
 import logging
+import MySQLdb
 
 from werkzeug.wrappers import Request, Response
 from werkzeug.local import LocalManager
@@ -70,6 +71,14 @@ def application(request):
 	except Exception, e:
 		http_status_code = getattr(e, "http_status_code", 500)
 
+		if (http_status_code==500
+			and isinstance(e, MySQLdb.OperationalError)
+			and e.args[0] in (1205, 1213)):
+				# 1205 = lock wait timeout
+				# 1213 = deadlock
+				# code 409 represents conflict
+				http_status_code = 409
+
 		if frappe.local.is_ajax:
 			response = frappe.utils.response.report_error(http_status_code)
 		else:
diff --git a/frappe/model/rename_doc.py b/frappe/model/rename_doc.py
index a4a8b73c09..d4e11252dd 100644
--- a/frappe/model/rename_doc.py
+++ b/frappe/model/rename_doc.py
@@ -82,7 +82,9 @@ def rename_parent_and_child(doctype, old, new, meta):
 	update_child_docs(old, new, meta)
 
 def validate_rename(doctype, new, meta, merge, force, ignore_permissions):
-	exists = frappe.db.get_value(doctype, new)
+	# using for update so that it gets locked and someone else cannot edit it while this rename is going on!
+	exists = frappe.db.sql("select name from `tab{doctype}` where name=%s for update".format(doctype=doctype), new)
+	exists = exists[0][0] if exists else None
 
 	if merge and not exists:
 		frappe.msgprint(_("{0} {1} does not exist, select a new target to merge").format(doctype, new), raise_exception=1)
diff --git a/frappe/public/js/frappe/request.js b/frappe/public/js/frappe/request.js
index 1618d213e5..50145a155d 100644
--- a/frappe/public/js/frappe/request.js
+++ b/frappe/public/js/frappe/request.js
@@ -66,6 +66,9 @@ frappe.request.call = function(opts) {
 
 			msgprint(__("Not permitted"));
 		},
+		409: function(xhr) {
+			msgprint(__("Another transaction is blocking this one. Please try again in a few seconds."));
+		},
 		417: function(data, xhr) {
 			if(typeof data === "string") data = JSON.parse(data);
 			opts.error_callback && opts.error_callback(data, xhr.responseText);