diff --git a/packages/base64/base64.3.5.0/opam b/packages/base64/base64.3.5.0/opam
index 680fe9ddbb6..acda34fb75f 100644
--- a/packages/base64/base64.3.5.0/opam
+++ b/packages/base64/base64.3.5.0/opam
@@ -20,6 +20,7 @@ depends: [
   "bos" {with-test}
   "rresult" {with-test}
   "alcotest" {with-test}
+  "base-bytes"
 ]
 build: [
   ["dune" "subst"] {dev}