diff --git a/src/dune_rules/merlin.ml b/src/dune_rules/merlin.ml
index da282eee569..349b0f0e973 100644
--- a/src/dune_rules/merlin.ml
+++ b/src/dune_rules/merlin.ml
@@ -131,7 +131,7 @@ module Processed = struct
     if String.need_quoting s then Filename.quote s else s
 
   let to_dot_merlin stdlib_dir pp_configs flags obj_dirs src_dirs extensions
-      (* TODO print melange flag *) _mode =
+      mode =
     let b = Buffer.create 256 in
     let printf = Printf.bprintf b in
     let print = Buffer.add_string b in
@@ -156,6 +156,11 @@ module Processed = struct
           print "# FLG";
           List.iter flags ~f:(fun f -> printf " %s" (quote_for_dot_merlin f));
           print "\n");
+    let () =
+      match mode with
+      | `Ocaml -> ()
+      | `Melange -> print "# FLG -ppx melc -as-ppx -bs-jsx 3\n"
+    in
     Buffer.contents b
 
   let get { modules; pp_config; config } ~filename =
diff --git a/test/blackbox-tests/test-cases/melange/merlin.t b/test/blackbox-tests/test-cases/melange/merlin.t
index d64fa56516a..902730b52bf 100644
--- a/test/blackbox-tests/test-cases/melange/merlin.t
+++ b/test/blackbox-tests/test-cases/melange/merlin.t
@@ -49,3 +49,11 @@ The melange.emit entry contains a ppx directive
 
   $ dune ocaml merlin dump-config $PWD | grep -i "ppx"
    (FLG (-ppx "melc -as-ppx -bs-jsx 3"))
+
+  $ dune ocaml dump-dot-merlin $PWD
+  EXCLUDE_QUERY_DIR
+  STDLIB /home/me/code/dune/_opam/lib/melange
+  B $TESTCASE_ROOT/_build/default/.output.mobjs/melange
+  S $TESTCASE_ROOT
+  # FLG -w @1..3@5..28@30..39@43@46..47@49..57@61..62@67@69-40 -strict-sequence -strict-formats -short-paths -keep-locs
+  # FLG -ppx melc -as-ppx -bs-jsx 3