diff --git a/pkgs/development/compilers/ghc/with-packages.nix b/pkgs/development/compilers/ghc/with-packages.nix
index f4f567f30b39..07071ef8414a 100644
--- a/pkgs/development/compilers/ghc/with-packages.nix
+++ b/pkgs/development/compilers/ghc/with-packages.nix
@@ -79,7 +79,12 @@ stdenv.mkDerivation rec {
     echo -n "Generating wrappers "
 
     for prg in ghc ghci ghc-${ghc.version} ghci-${ghc.version}; do
-      makeWrapper ${ghc}/bin/$prg $out/bin/$prg --add-flags "-B$linkedTopDir"
+      # The NIX env-vars are picked up by our patched version of ghc-paths.
+      makeWrapper ${ghc}/bin/$prg $out/bin/$prg \
+        --add-flags "-B$linkedTopDir" \
+        --set "NIX_GHC"        "$out/bin/ghc"     \
+        --set "NIX_GHCPKG"     "$out/bin/ghc-pkg" \
+        --set "NIX_GHC_LIBDIR" "$linkedTopDir"
       echo -n .
     done
 
diff --git a/pkgs/development/libraries/haskell/ghc-paths/default.nix b/pkgs/development/libraries/haskell/ghc-paths/default.nix
index 9d63c04514b4..b930e993dcc4 100644
--- a/pkgs/development/libraries/haskell/ghc-paths/default.nix
+++ b/pkgs/development/libraries/haskell/ghc-paths/default.nix
@@ -4,6 +4,7 @@ cabal.mkDerivation (self: {
   pname = "ghc-paths";
   version = "0.1.0.9";
   sha256 = "0ibrr1dxa35xx20cpp8jzgfak1rdmy344dfwq4vlq013c6w8z9mg";
+  patches = [ ./ghc-paths-nix.patch ];
   meta = {
     description = "Knowledge of GHC's installation directories";
     license = self.stdenv.lib.licenses.bsd3;
diff --git a/pkgs/development/libraries/haskell/ghc-paths/ghc-paths-nix.patch b/pkgs/development/libraries/haskell/ghc-paths/ghc-paths-nix.patch
new file mode 100644
index 000000000000..0b09f1fcf2e6
--- /dev/null
+++ b/pkgs/development/libraries/haskell/ghc-paths/ghc-paths-nix.patch
@@ -0,0 +1,32 @@
+diff -Naur ghc-paths-0.1.0.9/GHC/Paths.hs ghc-paths-0.1.0.9-new/GHC/Paths.hs
+--- ghc-paths-0.1.0.9/GHC/Paths.hs	2012-12-16 13:53:45.720148396 +0100
++++ ghc-paths-0.1.0.9-new/GHC/Paths.hs	2012-12-16 13:51:50.073070123 +0100
+@@ -4,10 +4,24 @@
+         ghc, ghc_pkg, libdir, docdir
+   ) where
+ 
++import Data.Maybe
++import System.Environment
++import System.IO.Unsafe
++
++nixLibdir, nixDocdir, nixGhc, nixGhcPkg :: Maybe FilePath
++nixLibdir = unsafePerformIO (lookupEnv "NIX_GHC_LIBDIR")
++nixDocdir = unsafePerformIO (lookupEnv "NIX_GHC_DOCDIR")
++nixGhc    = unsafePerformIO (lookupEnv "NIX_GHC")
++nixGhcPkg = unsafePerformIO (lookupEnv "NIX_GHCPKG")
++{-# NOINLINE nixLibdir #-}
++{-# NOINLINE nixDocdir #-}
++{-# NOINLINE nixGhc    #-}
++{-# NOINLINE nixGhcPkg #-}
++
+ libdir, docdir, ghc, ghc_pkg :: FilePath
+ 
+-libdir  = GHC_PATHS_LIBDIR
+-docdir  = GHC_PATHS_DOCDIR
++libdir  = fromMaybe GHC_PATHS_LIBDIR  nixLibdir
++docdir  = fromMaybe GHC_PATHS_DOCDIR  nixDocdir
+ 
+-ghc     = GHC_PATHS_GHC
+-ghc_pkg = GHC_PATHS_GHC_PKG
++ghc     = fromMaybe GHC_PATHS_GHC     nixGhc
++ghc_pkg = fromMaybe GHC_PATHS_GHC_PKG nixGhcPkg