diff --git a/pkgs/development/libraries/haskell/monad-par/0.3.4.2.nix b/pkgs/development/libraries/haskell/monad-par/0.3.4.2.nix
new file mode 100644
index 00000000000..ab875b34c36
--- /dev/null
+++ b/pkgs/development/libraries/haskell/monad-par/0.3.4.2.nix
@@ -0,0 +1,28 @@
+{ cabal, abstractDeque, abstractPar, deepseq, HUnit, monadParExtras
+, mtl, mwcRandom, parallel, QuickCheck, testFramework
+, testFrameworkHunit, testFrameworkQuickcheck2, testFrameworkTh
+, time
+}:
+
+cabal.mkDerivation (self: {
+  pname = "monad-par";
+  version = "0.3.4.2";
+  sha256 = "1k10m4w2g92psahsvcyi98sc31wg5anijp46lbsipi2r2gxxc7bs";
+  buildDepends = [
+    abstractDeque abstractPar deepseq monadParExtras mtl mwcRandom
+    parallel
+  ];
+  testDepends = [
+    abstractDeque abstractPar deepseq HUnit monadParExtras mtl
+    mwcRandom QuickCheck testFramework testFrameworkHunit
+    testFrameworkQuickcheck2 testFrameworkTh time
+  ];
+  doCheck = false;
+  meta = {
+    homepage = "https://github.com/simonmar/monad-par";
+    description = "A library for parallel programming based on a monad";
+    license = self.stdenv.lib.licenses.bsd3;
+    platforms = self.ghc.meta.platforms;
+    maintainers = [ self.stdenv.lib.maintainers.andres ];
+  };
+})
diff --git a/pkgs/top-level/haskell-packages.nix b/pkgs/top-level/haskell-packages.nix
index 9f99a49dd6d..90918c53638 100644
--- a/pkgs/top-level/haskell-packages.nix
+++ b/pkgs/top-level/haskell-packages.nix
@@ -1378,7 +1378,8 @@ let result = let callPackage = x : y : modifyPrio (newScope result.final x y);
 
   monadPar_0_1_0_3 = callPackage ../development/libraries/haskell/monad-par/0.1.0.3.nix {};
   monadPar_0_3_4_1 = callPackage ../development/libraries/haskell/monad-par/0.3.4.1.nix {};
-  monadPar = self.monadPar_0_3_4_1;
+  monadPar_0_3_4_2 = callPackage ../development/libraries/haskell/monad-par/0.3.4.2.nix {};
+  monadPar = self.monadPar_0_3_4_2;
 
   monadParExtras = callPackage ../development/libraries/haskell/monad-par-extras {};