diff --git a/pkgs/development/ocaml-modules/piqi/default.nix b/pkgs/development/ocaml-modules/piqi/default.nix
index b52c73d0534e..fb5f0192c459 100644
--- a/pkgs/development/ocaml-modules/piqi/default.nix
+++ b/pkgs/development/ocaml-modules/piqi/default.nix
@@ -1,5 +1,8 @@
 { lib, stdenv, fetchFromGitHub, ocaml, findlib, which, sedlex, easy-format, xmlm, base64 }:
 
+lib.throwIf (lib.versionAtLeast ocaml.version "5.0")
+  "piqi is not available for OCaml ${ocaml.version}"
+
 stdenv.mkDerivation rec {
   version = "0.6.16";
   pname = "piqi";