diff --git a/CHANGELOG.md b/CHANGELOG.md
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,5 +1,9 @@
 # Revision history for monadic-recursion-schemes
 
+## 0.1.6.0 -- 2020-05-15
+
+* add preproM and postproM.
+
 ## 0.1.5.0 -- 2020-05-14
 
 * add mutuM and comutuM with the other variant, which has not the same type signature.
diff --git a/monadic-recursion-schemes.cabal b/monadic-recursion-schemes.cabal
--- a/monadic-recursion-schemes.cabal
+++ b/monadic-recursion-schemes.cabal
@@ -4,7 +4,7 @@
 -- http://haskell.org/cabal/users-guide/
 
 name:                monadic-recursion-schemes
-version:             0.1.5.0
+version:             0.1.6.0
 synopsis:            Recursion Schemes for Monadic version.
 description:         Yet another recursion schemes for monadic style, depends on recursion-schemes.
 homepage:            https://github.com/cutsea110/monadic-recursion-schemes.git
diff --git a/src/Data/Functor/Foldable/Monadic.hs b/src/Data/Functor/Foldable/Monadic.hs
--- a/src/Data/Functor/Foldable/Monadic.hs
+++ b/src/Data/Functor/Foldable/Monadic.hs
@@ -238,4 +238,20 @@
          -> b -> m t
 comutuM' f psi = anaM psi . f
 
+-- | prepromorphism
+preproM :: (Monad m, Traversable (Base t), Recursive t, Corecursive t)
+        => (Base t t -> m (Base t t)) -- ^ monadic natural transformation
+        -> (Base t a -> m a)          -- ^ algebra
+        -> t -> m a
+preproM h phi = u
+  where u = phi <=< mapM f . project
+        f = u <=< cataM (return . embed <=< h)
 
+-- | postpromorphism
+postproM :: (Monad m, Traversable (Base t), Recursive t, Corecursive t)
+         => (Base t t -> m (Base t t)) -- ^ monadic natural transformation
+         -> (a -> m (Base t a))        -- ^ coalgebra
+         -> a -> m t
+postproM h psi = u
+  where u = return . embed <=< mapM f <=< psi
+        f = anaM (h . project) <=< u