diff --git a/mstate.cabal b/mstate.cabal
--- a/mstate.cabal
+++ b/mstate.cabal
@@ -8,7 +8,7 @@
 Author:         Nils Schweinsberg
 Maintainer:     <mail@n-sch.de>
 
-Version:        0.1.1
+Version:        0.1.2
 Category:       Concurrent, Monads
 License:        BSD3
 License-File:   LICENSE
diff --git a/src/Control/Concurrent/MState.hs b/src/Control/Concurrent/MState.hs
--- a/src/Control/Concurrent/MState.hs
+++ b/src/Control/Concurrent/MState.hs
@@ -210,7 +210,7 @@
     ask       = lift ask
     local f m = MState $ \s -> local f (runMState' m s)
 
-instance (MonadIO m, MonadWriter w m) => MonadWriter w (MState t m) where
+instance (MonadWriter w m) => MonadWriter w (MState t m) where
     tell     = lift . tell
     listen m = MState $ listen . runMState' m
     pass   m = MState $ pass   . runMState' m