diff --git a/plugins/Parter.py b/plugins/Parter.py
index 8d04d10eb..334e99160 100644
--- a/plugins/Parter.py
+++ b/plugins/Parter.py
@@ -67,7 +67,7 @@ def configure(advanced):
 
 conf.registerPlugin('Parter')
 conf.registerGlobalValue(conf.supybot.plugins.Parter, 'channels',
-    conf.SpaceSeparatedListOfChannels([], """Determines what channels the bot
+    conf.SpaceSeparatedSetOfChannels([], """Determines what channels the bot
     will automatically part whenever it joins them."""))
 
 class Parter(callbacks.Privmsg):
diff --git a/src/Admin.py b/src/Admin.py
index c063fa2c8..065f9a954 100755
--- a/src/Admin.py
+++ b/src/Admin.py
@@ -63,7 +63,7 @@ class Admin(privmsgs.CapabilityCheckingPrivmsg):
         self.joins = {}
 
     def do376(self, irc, msg):
-        channels = conf.supybot.channels()
+        channels = list(conf.supybot.channels())
         utils.sortBy(lambda s: ',' not in s, channels)
         keys = []
         chans = []
@@ -132,7 +132,7 @@ class Admin(privmsgs.CapabilityCheckingPrivmsg):
             if conf.supybot.alwaysJoinOnInvite() or \
                ircdb.checkCapability(msg.prefix, 'admin'):
                 irc.queueMsg(ircmsgs.join(channel))
-                conf.supybot.channels().append(channel)
+                conf.supybot.channels().add(channel)
     
     def join(self, irc, msg, args):
         """<channel>[,<key>] [<channel>[,<key>] ...]
@@ -157,7 +157,7 @@ class Admin(privmsgs.CapabilityCheckingPrivmsg):
             if not ircutils.isChannel(channel):
                 irc.error('%r is not a valid channel.' % channel)
                 return
-            conf.supybot.channels().append(original)
+            conf.supybot.channels().add(original)
         irc.queueMsg(ircmsgs.joins(channels, keys))
         for channel in channels:
             self.joins[channel] = (irc, msg)
diff --git a/src/conf.py b/src/conf.py
index 20d27b1ca..ef2ea467d 100644
--- a/src/conf.py
+++ b/src/conf.py
@@ -108,13 +108,14 @@ what server the bot connects to."""))
 supybot.register('password', registry.String('', """Determines the password to
 be sent to the server if it requires one."""))
 
-class SpaceSeparatedListOfChannels(registry.SeparatedListOf):
+class SpaceSeparatedSetOfChannels(registry.SeparatedListOf):
+    List = ircutils.IrcSet
     Value = ValidChannel
     def splitter(self, s):
         return s.split()
     joiner = ' '.join
 
-supybot.register('channels', SpaceSeparatedListOfChannels(['#supybot'], """
+supybot.register('channels', SpaceSeparatedSetOfChannels(['#supybot'], """
 Determines what channels the bot will join when it connects to the server."""))
 
 class ValidPrefixChars(registry.String):