diff --git a/Control/Monad/Trans/List.hs b/Control/Monad/Trans/List.hs
--- a/Control/Monad/Trans/List.hs
+++ b/Control/Monad/Trans/List.hs
@@ -145,8 +145,8 @@
 
 instance (MonadFix m) => MonadFix (ListT m) where
     mfix f = ListT $ mfix (runListT . f . head) >>= \ xs -> case xs of
-        [] -> pure []
-        x:_ -> (x:) <$> (runListT . mfix) ((mapListT . fmap) tail . f)
+        [] -> return []
+        x:_ -> liftM (x:) (runListT (mfix (mapListT (fmap tail) . f)))
     {-# INLINE mfix #-}
 
 instance MonadTrans ListT where
diff --git a/changelog b/changelog
--- a/changelog
+++ b/changelog
@@ -1,5 +1,8 @@
 -*-change-log-*-
 
+0.5.6.1 Ross Paterson <R.Paterson@city.ac.uk> Feb 2019
+	* Backward compatability fix for MonadFix ListT instance
+
 0.5.6.0 Ross Paterson <R.Paterson@city.ac.uk> Feb 2019
 	* Generalized type of except
 	* Added Control.Monad.Trans.Writer.CPS and Control.Monad.Trans.RWS.CPS
diff --git a/transformers.cabal b/transformers.cabal
--- a/transformers.cabal
+++ b/transformers.cabal
@@ -1,5 +1,5 @@
 name:         transformers
-version:      0.5.6.0
+version:      0.5.6.1
 license:      BSD3
 license-file: LICENSE
 author:       Andy Gill, Ross Paterson