diff --git a/ocaml-ocplib-simplex.spec b/ocaml-ocplib-simplex.spec
index 058052e..c594fcf 100644
--- a/ocaml-ocplib-simplex.spec
+++ b/ocaml-ocplib-simplex.spec
@@ -18,6 +18,7 @@ Source0:        https://github.com/OCamlPro-Iguernlala/%{pkgname}/archive/%{vers
 BuildRequires:  autoconf
 BuildRequires:  ocaml
 BuildRequires:  ocaml-findlib
+BuildRequires:  ocaml-num-devel
 
 %description
 This package contains a library implementing a simplex algorithm, in a