diff --git a/pkgs/development/ocaml-modules/ocamlnet/default.nix b/pkgs/development/ocaml-modules/ocamlnet/default.nix
index 1da80a2202d7..bdbbf1d8c67f 100644
--- a/pkgs/development/ocaml-modules/ocamlnet/default.nix
+++ b/pkgs/development/ocaml-modules/ocamlnet/default.nix
@@ -1,4 +1,4 @@
-{ stdenv, lib, fetchurl, pkg-config, ncurses, ocaml, findlib, ocaml_pcre, camlzip
+{ stdenv, lib, fetchurl, pkg-config, which, ncurses, ocaml, findlib, ocaml_pcre, camlzip
 , gnutls, nettle
 }:
 
@@ -8,14 +8,14 @@ else
 
 stdenv.mkDerivation rec {
   name = "ocaml${ocaml.version}-ocamlnet-${version}";
-  version = "4.1.8";
+  version = "4.1.9";
 
   src = fetchurl {
     url = "http://download.camlcity.org/download/ocamlnet-${version}.tar.gz";
-    sha256 = "1x703mjqsv9nvffnkj5i36ij2s5zfvxxll2z1qj6a7p428b2yfnm";
+    sha256 = "1vlwxjxr946gdl61a1d7yk859cijq45f60dhn54ik3w4g6cx33pr";
   };
 
-  nativeBuildInputs = [ pkg-config ];
+  nativeBuildInputs = [ pkg-config which ];
   buildInputs = [ ncurses ocaml findlib ocaml_pcre camlzip gnutls nettle ];
 
   createFindlibDestdir = true;