diff --git a/opam b/opam
index 6a5df8d..7ffdd9a 100644
--- a/opam
+++ b/opam
@@ -26,4 +26,7 @@ install: [ make "install" ]
 
 remove: [ "ocamlfind" "remove" "ISO8601" ]
 
-depends: [ "ocamlfind" ]
+depends: [
+  "ocamlfind" {build}
+  "ocamlbuild" {build}
+]