diff --git a/Control/Monad/Trans/Resource.hs b/Control/Monad/Trans/Resource.hs
--- a/Control/Monad/Trans/Resource.hs
+++ b/Control/Monad/Trans/Resource.hs
@@ -125,7 +125,7 @@
 -- unwrapped before calling @runResourceT@.
 --
 -- Since 0.3.0
-class (MonadThrow m, MonadUnsafeIO m, MonadIO m) => MonadResource m where
+class (MonadThrow m, MonadUnsafeIO m, MonadIO m, Applicative m) => MonadResource m where
     -- | Register some action that will be called precisely once, either when
     -- 'runResourceT' is called, or when the 'ReleaseKey' is passed to 'release'.
     --
@@ -157,7 +157,7 @@
     -- Since 0.3.0
     resourceMask :: ((forall a. ResourceT IO a -> ResourceT IO a) -> ResourceT IO b) -> m b
 
-instance (MonadThrow m, MonadUnsafeIO m, MonadIO m) => MonadResource (ResourceT m) where
+instance (MonadThrow m, MonadUnsafeIO m, MonadIO m, Applicative m) => MonadResource (ResourceT m) where
     allocate acquire rel = ResourceT $ \istate -> liftIO $ E.mask $ \restore -> do
         a <- restore acquire
         key <- register' istate $ rel a
diff --git a/resourcet.cabal b/resourcet.cabal
--- a/resourcet.cabal
+++ b/resourcet.cabal
@@ -1,5 +1,5 @@
 Name:                resourcet
-Version:             0.3.0
+Version:             0.3.1
 Synopsis:            Deterministic allocation and freeing of scarce resources.
 Description:
 	This package was originally included with the conduit package, and has since been split off. For more information, please see <http://www.yesodweb.com/book/conduits>.