diff --git a/src/dot-merlin/dot_merlin_reader.ml b/src/dot-merlin/dot_merlin_reader.ml
index e219bbf22..ba889fe8e 100644
--- a/src/dot-merlin/dot_merlin_reader.ml
+++ b/src/dot-merlin/dot_merlin_reader.ml
@@ -457,6 +457,9 @@ let postprocess cfg =
       cfg.stdlib
       |> Option.map ~f:(fun stdlib -> `STDLIB stdlib)
       |> Option.to_list;
+      cfg.source_root
+      |> Option.map ~f:(fun source_root -> `SOURCE_ROOT source_root)
+      |> Option.to_list;
       List.concat_map pkg_paths ~f:(fun p -> [ `B p; `S p ]);
       ppx;
       List.map failures ~f:(fun s -> `ERROR_MSG s)
diff --git a/tests/test-dirs/config/dot-merlin-reader/load-config.t b/tests/test-dirs/config/dot-merlin-reader/load-config.t
index cd3b50f63..b765ff4fe 100644
--- a/tests/test-dirs/config/dot-merlin-reader/load-config.t
+++ b/tests/test-dirs/config/dot-merlin-reader/load-config.t
@@ -6,12 +6,13 @@ This test comes from: https://github.com/janestreet/merlin-jst/pull/59
   > BH build-hidden/dir
   > SH source-hidden/dir
   > STDLIB /stdlib
+  > SOURCE_ROOT /root
   > EOF
 
   $ FILE=$(pwd)/test.ml; dot-merlin-reader <<EOF | sed 's#[0-9]*:#?:#g'
   > (4:File${#FILE}:$FILE)
   > EOF
-  ((?:B?:$TESTCASE_ROOT/build/dir)(?:S?:$TESTCASE_ROOT/source/dir)(?:ERROR?:Unknown tag in .merlin?: BH)(?:ERROR?:Unknown tag in .merlin?: SH)(?:STDLIB?:/stdlib))
+  ((?:B?:$TESTCASE_ROOT/build/dir)(?:S?:$TESTCASE_ROOT/source/dir)(?:ERROR?:Unknown tag in .merlin?: BH)(?:ERROR?:Unknown tag in .merlin?: SH)(?:STDLIB?:/stdlib)(?:SOURCE_ROOT?:/root))
 
   $ echo | $MERLIN single dump-configuration -filename test.ml 2> /dev/null | jq '.value.merlin'
   {
@@ -36,7 +37,7 @@ This test comes from: https://github.com/janestreet/merlin-jst/pull/59
       }
     ],
     "stdlib": "/stdlib",
-    "source_root": null,
+    "source_root": "/root",
     "unit_name": null,
     "wrapping_prefix": null,
     "reader": [],