diff --git a/src/chat_control.py b/src/chat_control.py
index baa9beec8..7b62ec6cd 100644
--- a/src/chat_control.py
+++ b/src/chat_control.py
@@ -1815,6 +1815,9 @@ class ChatControl(ChatControlBase):
 				encrypted = data[4], subject = data[1], xhtml = data[7])
 			if len(data) > 6 and isinstance(data[6], int):
 				message_ids.append(data[6])
+
+			if len(data) > 8:
+				self.set_thread_id(data[8])
 		if message_ids:
 			gajim.logger.set_read_messages(message_ids)
 		gajim.events.remove_events(self.account, jid_with_resource,
diff --git a/src/common/contacts.py b/src/common/contacts.py
index b309981d4..d6352cea6 100644
--- a/src/common/contacts.py
+++ b/src/common/contacts.py
@@ -16,6 +16,8 @@
 
 import common.gajim
 
+import random, string
+
 class Contact:
 	'''Information concerning each contact'''
 	def __init__(self, jid='', name='', groups=[], show='', status='', sub='',
@@ -50,6 +52,20 @@ class Contact:
 		self.chatstate = chatstate
 		self.last_status_time = last_status_time
 
+		# XEP-0201
+		self.sessions = {}
+
+	def new_session(self):
+		thread_id = "".join([random.choice(string.letters) for x in xrange(0,32)])
+		self.sessions[self.get_full_jid()] = thread_id
+		return thread_id
+
+	def get_session(self):
+		try:
+			return self.sessions[self.get_full_jid()]
+		except KeyError:
+			return None
+
 	def get_full_jid(self):
 		if self.resource:
 			return self.jid + '/' + self.resource
diff --git a/src/message_control.py b/src/message_control.py
index e2d16a45b..11b3b6996 100644
--- a/src/message_control.py
+++ b/src/message_control.py
@@ -37,6 +37,8 @@ class MessageControl:
 		self.hide_chat_buttons_current = False
 		self.resource = resource
 
+		self.thread_id = self.contact.get_session()
+
 		gajim.last_message_time[self.account][self.get_full_jid()] = 0
 
 		self.xml = gtkgui_helpers.get_glade('message_window.glade', widget_name)
@@ -110,14 +112,26 @@ class MessageControl:
 	def get_specific_unread(self):
 		return len(gajim.events.get_events(self.account, self.contact.jid))
 
+	def set_thread_id(self, thread_id):
+		if thread_id == self.thread_id:
+			return
+		if self.thread_id:
+			print "starting a new session, forgetting about the old one!"
+		self.thread_id = thread_id
+		self.contact.sessions[self.contact.get_full_jid()] = thread_id
+
 	def send_message(self, message, keyID = '', type = 'chat',
 	chatstate = None, msg_id = None, composing_jep = None, resource = None,
 	user_nick = None):
 		'''Send the given message to the active tab. Doesn't return None if error
 		'''
 		jid = self.contact.jid
+
+		if not self.thread_id:
+			self.thread_id = self.contact.new_session()
+
 		# Send and update history
 		return gajim.connections[self.account].send_message(jid, message, keyID,
 			type = type, chatstate = chatstate, msg_id = msg_id,
 			composing_jep = composing_jep, resource = self.resource,
-			user_nick = user_nick)
+			user_nick = user_nick, thread = self.thread_id)
diff --git a/src/roster_window.py b/src/roster_window.py
index b1c3700d0..4f0019aa5 100644
--- a/src/roster_window.py
+++ b/src/roster_window.py
@@ -3596,6 +3596,8 @@ class RosterWindow:
 			typ = ''
 			if msg_type == 'error':
 				typ = 'status'
+			if thread:
+				ctrl.set_thread_id(thread)
 			ctrl.print_conversation(msg, typ, tim = tim, encrypted = encrypted,
 						subject = subject, xhtml = xhtml)
 			if msg_id: