diff --git a/CHANGELOG.markdown b/CHANGELOG.markdown
--- a/CHANGELOG.markdown
+++ b/CHANGELOG.markdown
@@ -1,3 +1,7 @@
+0.6.4
+---
+* Allow exceptions 0.6
+
 0.6.3
 ---
 * Removed unused `array` dependency
diff --git a/src/Data/Functor/Trans/Tagged.hs b/src/Data/Functor/Trans/Tagged.hs
--- a/src/Data/Functor/Trans/Tagged.hs
+++ b/src/Data/Functor/Trans/Tagged.hs
@@ -37,7 +37,7 @@
 #endif
 import Control.Applicative (Alternative(..), Applicative(..), (<$), (<$>))
 import Control.Monad (liftM, MonadPlus(..))
-import Control.Monad.Catch (MonadCatch(..), MonadThrow(..))
+import Control.Monad.Catch (MonadCatch(..), MonadThrow(..), MonadMask(..))
 import Control.Monad.Fix (MonadFix(..))
 import Control.Monad.Trans (MonadIO(..), MonadTrans(..))
 import Control.Monad.Reader (MonadReader(..))
@@ -227,6 +227,8 @@
 instance MonadCatch m => MonadCatch (TaggedT s m) where
   catch m f = tag (catch (untag m) (untag . f))
   {-# INLINE catch #-}
+
+instance MonadMask m => MonadMask (TaggedT s m) where
   mask a = tag $ mask $ \u -> untag (a $ q u)
     where q u = tag . u . untag
   {-# INLINE mask #-}
diff --git a/tagged-transformer.cabal b/tagged-transformer.cabal
--- a/tagged-transformer.cabal
+++ b/tagged-transformer.cabal
@@ -1,5 +1,5 @@
 name:           tagged-transformer
-version:        0.6.3
+version:        0.6.4
 license:        BSD3
 license-file:   LICENSE
 author:         Edward A. Kmett
@@ -30,7 +30,7 @@
     comonad                   >= 4        && < 5,
     contravariant             >= 0.3      && < 1,
     distributive              >= 0.3      && < 1,
-    exceptions                >= 0.4      && < 1,
+    exceptions                >= 0.6      && < 1,
     mtl                       >= 2.0.1    && < 2.2,
     reflection                >= 1.1.6    && < 2,
     semigroupoids             >= 4        && < 5,