diff --git a/biotk.opam b/biotk.opam
index 5e16d12..fa82f54 100644
--- a/biotk.opam
+++ b/biotk.opam
@@ -13,6 +13,7 @@ homepage: "https://github.com/pveber/biotk/"
 bug-reports: "https://github.com/pveber/biotk/issues"
 depends: [
   "dune" {>= "2.7"}
+  "angstrom" {>= "0.15.0"}
   "angstrom-unix" {>= "0.15.0"}
   "biocaml"
   "core" {>= "v0.14.0"}
diff --git a/dune-project b/dune-project
index 6cbc26a..292d4b4 100644
--- a/dune-project
+++ b/dune-project
@@ -17,6 +17,7 @@
                 file formats, a few basic data structures and sequence
                 algorithms, as well as access to some databases.")
   (depends
+    ("angstrom" (>= 0.15.0))
     ("angstrom-unix" (>= 0.15.0))
     "biocaml"
     ("core" (>= "v0.14.0"))