diff --git a/Control/DeepSeq.hs b/Control/DeepSeq.hs
index 70e7206..84af949 100644
--- a/Control/DeepSeq.hs
+++ b/Control/DeepSeq.hs
@@ -139,7 +139,7 @@ import GHC.Tuple (Solo (..))
 #endif
 
 #if BYTEARRAY_IN_BASE
-import Data.Array.Byte (ByteArray(..))
+import Data.Array.Byte (ByteArray(..), MutableByteArray(..))
 #endif
 
 -- | Hidden internal type-class
@@ -968,7 +968,11 @@ instance (NFData a1, NFData a2, NFData a3, NFData a4, NFData a5, NFData a6, NFDa
 -- ByteArray
 
 #if BYTEARRAY_IN_BASE
--- |@since 1.4.6.0
+-- |@since 1.4.7.0
 instance NFData ByteArray where
   rnf (ByteArray _) = ()
+
+-- |@since 1.4.8.0
+instance NFData (MutableByteArray s) where
+  rnf (MutableByteArray _) = ()
 #endif
diff --git a/changelog.md b/changelog.md
index 0cb324e..dea0ead 100644
--- a/changelog.md
+++ b/changelog.md
@@ -1,5 +1,10 @@
 # Changelog for [`deepseq` package](http://hackage.haskell.org/package/deepseq)
 
+## 1.4.8.0
+
+  * Add `NFData` instance for `MutableByteArray`
+    ([#84](https://github.com/haskell/deepseq/pull/84))
+
 ## 1.4.7.0
 
   * Add instances for `Solo` (GHC-9)
diff --git a/deepseq.cabal b/deepseq.cabal
index 323f16f..b81786f 100644
--- a/deepseq.cabal
+++ b/deepseq.cabal
@@ -1,6 +1,6 @@
 cabal-version:  1.12
 name:           deepseq
-version:        1.4.7.0
+version:        1.4.8.0
 -- NOTE: Don't forget to update ./changelog.md
 
 license:        BSD3