diff --git a/CHANGELOG.md b/CHANGELOG.md
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,6 +1,11 @@
 Changes
 =======
 
+Version 1.1.3
+-------------
+
+* Add `Serial` and `CoSerial` instances for `Word` and `Natural`
+
 Version 1.1.2
 -------------
 
diff --git a/Test/SmallCheck/Series.hs b/Test/SmallCheck/Series.hs
--- a/Test/SmallCheck/Series.hs
+++ b/Test/SmallCheck/Series.hs
@@ -189,6 +189,8 @@
 import Control.Monad.Identity
 import Data.List
 import Data.Ratio
+import Data.Word (Word)
+import Numeric.Natural (Natural)
 import Test.SmallCheck.SeriesMonad
 import GHC.Generics
 
@@ -484,6 +486,16 @@
   series = (toInteger :: Int -> Integer) <$> series
 instance Monad m => CoSerial m Integer where
   coseries rs = (. (fromInteger :: Integer->Int)) <$> coseries rs
+
+instance Monad m => Serial m Natural where
+  series = (fromIntegral :: N Int -> Natural) <$> series
+instance Monad m => CoSerial m Natural where
+  coseries rs = (. (fromIntegral :: Natural->Int)) <$> coseries rs
+
+instance Monad m => Serial m Word where
+  series = (fromIntegral :: N Int -> Word) <$> series
+instance Monad m => CoSerial m Word where
+  coseries rs = (. (fromIntegral :: Word->Int)) <$> coseries rs
 
 -- | 'N' is a wrapper for 'Integral' types that causes only non-negative values
 -- to be generated. Generated functions of type @N a -> b@ do not distinguish
diff --git a/smallcheck.cabal b/smallcheck.cabal
--- a/smallcheck.cabal
+++ b/smallcheck.cabal
@@ -1,5 +1,5 @@
 Name:          smallcheck
-Version:       1.1.2
+Version:       1.1.3
 Cabal-Version: >= 1.6
 License:       BSD3
 License-File:  LICENSE