diff --git a/plugins/relay.py b/plugins/relay.py
index 07eaaf9..8201048 100644
--- a/plugins/relay.py
+++ b/plugins/relay.py
@@ -663,13 +663,19 @@ def relayJoins(irc, channel, users, ts, modes):
             log.debug('Okay, spawning %s/%s everywhere', user, irc.name)
             assert user in irc.users, "(%s) How is this possible? %r isn't in our user database." % (irc.name, user)
             u = getRemoteUser(irc, remoteirc, user)
-            ts = irc.channels[channel].ts
-            # TODO: join users in batches with SJOIN, not one by one.
-            prefixes = getPrefixModes(irc, remoteirc, channel, user)
-            userpair = (prefixes, u)
-            queued_users.append(userpair)
-            log.debug('(%s) relayJoins: joining %s to %s%s', irc.name, userpair, remoteirc.name, remotechan)
-        remoteirc.proto.sjoinServer(remoteirc, remoteirc.sid, remotechan, queued_users, ts=ts)
+            # Only join users if they aren't already joined. This prevents op floods
+            # on charybdis from all the SJOINing.
+            if u not in remoteirc.channels[channel].users:
+                ts = irc.channels[channel].ts
+                prefixes = getPrefixModes(irc, remoteirc, channel, user)
+                userpair = (prefixes, u)
+                queued_users.append(userpair)
+                log.debug('(%s) relayJoins: joining %s to %s%s', irc.name, userpair, remoteirc.name, remotechan)
+            else:
+                log.debug('(%s) relayJoins: not joining %s to %s%s; they\'re already there!', irc.name,
+                          u, remoteirc.name, remotechan)
+        if queued_users:
+            remoteirc.proto.sjoinServer(remoteirc, remoteirc.sid, remotechan, queued_users, ts=ts)
         relayModes(irc, remoteirc, irc.sid, channel, modes)
 
 def relayPart(irc, channel, user):