diff --git a/Changelog.draft.rst b/Changelog.draft.rst
index ed3a14e..ff559a0 100644
--- a/Changelog.draft.rst
+++ b/Changelog.draft.rst
@@ -13,6 +13,11 @@ others.
 New Features
 ------------
 
+* Enable 1-way synchronization by settting a [Repository ...] to
+  readonly = True. When e.g. using offlineimap for backup purposes you
+  can thus make sure that no changes in your backup trickle back into
+  the main IMAP server.
+
 Changes
 -------
 
diff --git a/offlineimap.conf b/offlineimap.conf
index 7018090..f8506b2 100644
--- a/offlineimap.conf
+++ b/offlineimap.conf
@@ -1,6 +1,5 @@
 # Sample configuration file
-# Copyright (C) 2002-2005 John Goerzen
-# <jgoerzen@complete.org>
+# Copyright (C) 2002-2011 John Goerzen & contributors
 #
 #    This program is free software; you can redistribute it and/or modify
 #    it under the terms of the GNU General Public License as published by
@@ -67,13 +66,14 @@ maxsyncaccounts = 1
 
 ui = Blinkenlights
 
-# If you try to synchronize messages to a read-only folder,
-# OfflineIMAP will generate a warning.  If you want to suppress these
-# warnings, set ignore-readonly to yes.  Read-only IMAP folders allow
-# reading but not modification, so if you try to change messages in
-# the local copy of such a folder, the IMAP server will prevent
-# OfflineIMAP from propagating those changes to the IMAP server.
-
+# If you try to synchronize messages to a folder which the IMAP server
+# considers read-only, OfflineIMAP will generate a warning.  If you want
+# to suppress these warnings, set ignore-readonly to yes.  Read-only
+# IMAP folders allow reading but not modification, so if you try to
+# change messages in the local copy of such a folder, the IMAP server
+# will prevent OfflineIMAP from propagating those changes to the IMAP
+# server.  Note that ignore-readonly is unrelated to the "readonly"
+# setting which prevents a repository from being modified at all.
 ignore-readonly = no
 
 ########## Advanced settings
@@ -469,6 +469,11 @@ subscribedonly = no
 #
 # foldersort = lambda x, y: -cmp(x, y)
 
+# Enable 1-way synchronization. When setting 'readonly' to True, this
+# repository will not be modified during synchronization. Use to
+# e.g. backup an IMAP server. The readonly setting can be applied to any
+# type of Repository (Maildir, Imap, etc).
+readonly = False
 
 [Repository GmailExample]
 
@@ -509,3 +514,5 @@ realdelete = no
 #
 # spamfolder = [Google Mail]/Spam
 
+# Enable 1-way synchronization. See above for explanation.
+readonly = False
diff --git a/offlineimap/accounts.py b/offlineimap/accounts.py
index c366810..0b71377 100644
--- a/offlineimap/accounts.py
+++ b/offlineimap/accounts.py
@@ -260,8 +260,10 @@ class SyncableAccount(Account):
             remoterepos = self.remoterepos
             localrepos = self.localrepos
             statusrepos = self.statusrepos
-            self.ui.syncfolders(remoterepos, localrepos)
-            remoterepos.syncfoldersto(localrepos, [statusrepos])
+            # replicate the folderstructure from REMOTE to LOCAL
+            if not localrepos.getconf('readonly', False):
+                self.ui.syncfolders(remoterepos, localrepos)
+                remoterepos.syncfoldersto(localrepos, [statusrepos])
 
             siglistener.addfolders(remoterepos.getfolders(), bool(self.refreshperiod), quick)
 
@@ -374,12 +376,20 @@ def syncfolder(accountname, remoterepos, remotefolder, localrepos,
                              remotefolder.getmessagecount())
 
         # Synchronize remote changes.
-        ui.syncingmessages(remoterepos, remotefolder, localrepos, localfolder)
-        remotefolder.syncmessagesto(localfolder, statusfolder)
+        if not localrepos.getconf('readonly', False):
+            ui.syncingmessages(remoterepos, remotefolder, localrepos, localfolder)
+            remotefolder.syncmessagesto(localfolder, statusfolder)
+        else:
+            ui.debug('imap', "Not syncing to read-only repository '%s'" \
+                         % localrepos.getname())
+        
         # Synchronize local changes
-        ui.syncingmessages(localrepos, localfolder, remoterepos, remotefolder)
-        localfolder.syncmessagesto(remotefolder, statusfolder)
-
+        if not remoterepos.getconf('readonly', False):
+            ui.syncingmessages(localrepos, localfolder, remoterepos, remotefolder)
+            localfolder.syncmessagesto(remotefolder, statusfolder)
+        else:
+            ui.debug('', "Not syncing to read-only repository '%s'" \
+                         % remoterepos.getname())
 
         statusfolder.save()
         localrepos.restore_atime()