diff --git a/src/Test/QuickCheck/Gen.hs b/src/Test/QuickCheck/Gen.hs
index 03a214f3..55aa1685 100644
--- a/src/Test/QuickCheck/Gen.hs
+++ b/src/Test/QuickCheck/Gen.hs
@@ -57,7 +57,7 @@ import Control.Applicative
 -- <http://hackage.haskell.org/package/quickcheck-transformer quickcheck-transformer>
 -- provide monad transformer versions of @Gen@.
 newtype Gen a = MkGen{
-  unGen :: QCGen -> Int -> a -- ^ Run the generator on a particular seed.
+  unGen :: QCGen -> Int -> a -- ^ Run the generator on a particular seed and size.
                              -- If you just want to get a random value out, consider using 'generate'.
   }