Well, I've managed to produce a solution, quite ugly and unefficient. Still it works (and I really need it). StdGen serialization occurs only once during computation that lasts several hours, so the speed is not vital for me. Here is my solution: module Main where import System.Random import Data.Binary import Data.Int data StdGen' = StdGen' Int32 Int32 deriving (Show) gen2gen' :: StdGen -> StdGen' gen2gen' gen = let [g1, g2] = words $ show $ gen g1' = read g1 :: Int32 g2' = read g2 :: Int32 in StdGen' g1' g2' gen'2gen :: StdGen' -> StdGen gen'2gen (StdGen' g1' g2') = let gen = read $ show g1' ++ ' ':(show g2') :: StdGen in gen instance Data.Binary.Binary StdGen' where put (StdGen' aa ab) = do Data.Binary.put aa Data.Binary.put ab get = do aa <- get ab <- get return (StdGen' aa ab) instance Data.Binary.Binary StdGen where put gen = put $ gen2gen' gen get = do gen' <- get return (gen'2gen gen')