diff --git a/source/Network/Xmpp/Concurrent.hs b/source/Network/Xmpp/Concurrent.hs
index dd7137f..65f22d2 100644
--- a/source/Network/Xmpp/Concurrent.hs
+++ b/source/Network/Xmpp/Concurrent.hs
@@ -121,13 +121,31 @@ handleIQ iqHands out sta as = do
     handleIQResponse :: TVar IQHandlers -> Either IQError IQResult -> IO ()
     handleIQResponse handlers iq = atomically $ do
         (byNS, byID) <- readTVar handlers
-        case Map.updateLookupWithKey (\_ _ -> Nothing) (iqID iq, iqFrom iq)
-                                     byID of
-            (Nothing, _) -> return () -- We are not supposed to send an error.
-            (Just tmvar, byID') -> do
-                let answer = Just (either IQResponseError IQResponseResult iq, as)
-                _ <- tryPutTMVar tmvar answer -- Don't block.
-                writeTVar handlers (byNS, byID')
+        case Map.updateLookupWithKey (\_ _ -> Nothing) (iqID iq) byID of
+            (Nothing, _) -> return () -- The handler might be removed due to
+                                      -- timeout
+            (Just (expectedJid, tmvar), byID') -> do
+                let expected = case expectedJid of
+                    -- IQ was sent to the server and we didn't have a bound JID
+                    -- We just accept any matching response
+                        Left Nothing -> True
+                    -- IQ was sent to the server and we had a bound JID. Valid
+                    -- responses might have no to attribute, the domain of the
+                    -- server, our bare JID or our full JID
+                        Left (Just j) -> case iqFrom iq of
+                            Nothing -> True
+                            Just jf -> jf <~ j
+                    -- IQ was sent to a (full) JID. The answer has to come from
+                    -- the same exact JID.
+                        Right j -> iqFrom iq == Just j
+                        _ -> False
+                case expected of
+                    True -> do
+                        let answer = Just (either IQResponseError
+                                                  IQResponseResult iq, as)
+                        _ <- tryPutTMVar tmvar answer -- Don't block.
+                        writeTVar handlers (byNS, byID')
+                    False -> return ()
       where
         iqID (Left err') = iqErrorID err'
         iqID (Right iq') = iqResultID iq'
diff --git a/source/Network/Xmpp/Concurrent/IQ.hs b/source/Network/Xmpp/Concurrent/IQ.hs
index 4234ff6..6817c24 100644
--- a/source/Network/Xmpp/Concurrent/IQ.hs
+++ b/source/Network/Xmpp/Concurrent/IQ.hs
@@ -5,13 +5,10 @@ import           Control.Applicative ((<$>))
 import           Control.Concurrent (forkIO)
 import           Control.Concurrent.STM
 import           Control.Concurrent.Thread.Delay (delay)
-
 import           Control.Monad
-
 import qualified Data.Map as Map
 import           Data.Text (Text)
 import           Data.XML.Types
-
 import           Network.Xmpp.Concurrent.Basic
 import           Network.Xmpp.Concurrent.Types
 import           Network.Xmpp.Types
@@ -31,14 +28,16 @@ sendIQ :: Maybe Integer -- ^ Timeout . When the timeout is reached the response
        -> Element -- ^ The IQ body (there has to be exactly one)
        -> Session
        -> IO (Either XmppFailure (TMVar (Maybe (Annotated IQResponse))))
-sendIQ timeOut to tp lang body session = do -- TODO: Add timeout
+sendIQ timeOut to tp lang body session = do
     newId <- idGenerator session
-    let key = (newId, to)
+    j <- case to of
+        Just t -> return $ Right t
+        Nothing -> Left <$> getJid session
     ref <- atomically $ do
         resRef <- newEmptyTMVar
+        let value = (j, resRef)
         (byNS, byId) <- readTVar (iqHandlers session)
-        writeTVar (iqHandlers session) (byNS, Map.insert key resRef byId)
-          -- TODO: Check for id collisions (shouldn't happen?)
+        writeTVar (iqHandlers session) (byNS, Map.insert newId value byId)
         return resRef
     res <- sendStanza (IQRequestS $ IQRequest newId Nothing to lang tp body) session
     case res of
@@ -47,7 +46,7 @@ sendIQ timeOut to tp lang body session = do -- TODO: Add timeout
                 Nothing -> return ()
                 Just t -> void . forkIO $ do
                           delay t
-                          doTimeOut (iqHandlers session) key ref
+                          doTimeOut (iqHandlers session) newId ref
             return $ Right ref
         Left e -> return $ Left e
   where
diff --git a/source/Network/Xmpp/Concurrent/Types.hs b/source/Network/Xmpp/Concurrent/Types.hs
index 4f2b605..415c1c4 100644
--- a/source/Network/Xmpp/Concurrent/Types.hs
+++ b/source/Network/Xmpp/Concurrent/Types.hs
@@ -135,7 +135,8 @@ data Session = Session
 -- TMVars of and TMVars for expected IQ responses (the second Text represent a
 -- stanza identifier.
 type IQHandlers = ( Map.Map (IQRequestType, Text) (TChan IQRequestTicket)
-                  , Map.Map (Text, Maybe Jid) (TMVar (Maybe (Annotated IQResponse)))
+                  , Map.Map Text (Either (Maybe Jid) Jid,
+                                  TMVar (Maybe (Annotated IQResponse)))
                   )
 
 -- | Contains whether or not a reply has been sent, and the IQ request body to
diff --git a/source/Network/Xmpp/Types.hs b/source/Network/Xmpp/Types.hs
index d14e4dd..6bd35a2 100644
--- a/source/Network/Xmpp/Types.hs
+++ b/source/Network/Xmpp/Types.hs
@@ -61,6 +61,7 @@ module Network.Xmpp.Types
     , isFull
     , jidFromText
     , jidFromTexts
+    , (<~)
     , nodeprepProfile
     , resourceprepProfile
     , jidToText
@@ -878,6 +879,19 @@ jidQ :: QuasiQuoter
 jidQ = jidQ
 #endif
 
+-- | The partial order of "definiteness". JID1 is less than or equal JID2 iff
+-- the domain parts are equal and JID1's local part and resource part each are
+-- either Nothing or equal to Jid2's
+(<~) :: Jid -> Jid -> Bool
+(Jid lp1 dp1 rp1) <~ (Jid lp2 dp2 rp2) =
+    dp1 ==  dp2 &&
+    lp1 ~<~ lp2 &&
+    rp1 ~<~ rp2
+  where
+   Nothing  ~<~ _ = True
+   Just x  ~<~ Just y = x == y
+   _  ~<~ _ = False
+
 -- Produces a LangTag value in the format "parseLangTag \"<jid>\"".
 instance Show LangTag where
   show l = "parseLangTag " ++ show (langTagToText l)