diff --git a/CHANGES.md b/CHANGES.md
index 99010a2..3f8145c 100644
--- a/CHANGES.md
+++ b/CHANGES.md
@@ -1,7 +1,7 @@
 NEXT RELEASE
 ------------
 
-...
+- Use `MUTAML_DIFF_COMMAND="gdiff -u"` in cram tests on FreeBSD for consistent output #53
 
 0.4
 ---
diff --git a/test/instrumentation-tests/function-merge-consecutive.t b/test/instrumentation-tests/function-merge-consecutive.t
index e0d3bc8..c8ce2bc 100644
--- a/test/instrumentation-tests/function-merge-consecutive.t
+++ b/test/instrumentation-tests/function-merge-consecutive.t
@@ -4,6 +4,9 @@ Create dune and dune-project files:
   $ export MUTAML_SEED=896745231
   $ export MUTAML_MUT_RATE=100
 
+Use gdiff on FreeBSD:
+  $ if [ -x "$(command -v uname)" ] && [ $(uname -s) = "FreeBSD" ]; then export MUTAML_DIFF_COMMAND="gdiff -u"; fi
+
 
 An example with only conservative, GADT-safe mutations:
 --------------------------------------------------------------------------------
diff --git a/test/instrumentation-tests/match.t b/test/instrumentation-tests/match.t
index edc65f5..af72e2e 100644
--- a/test/instrumentation-tests/match.t
+++ b/test/instrumentation-tests/match.t
@@ -1,6 +1,9 @@
 Create dune and dune-project files:
   $ bash ../write_dune_files.sh
 
+Use gdiff on FreeBSD:
+  $ if [ -x "$(command -v uname)" ] && [ $(uname -s) = "FreeBSD" ]; then export MUTAML_DIFF_COMMAND="gdiff -u"; fi
+
 Make an .ml-file:
   $ cat > test.ml <<'EOF'
   > let () = match !Sys.interactive with