diff --git a/spec/libsass-todo-issues/issue_628/expected_output.css b/spec/libsass-todo-issues/issue_628/expected_output.css
new file mode 100644
index 0000000000..e817a25497
--- /dev/null
+++ b/spec/libsass-todo-issues/issue_628/expected_output.css
@@ -0,0 +1 @@
+Duplicate key "eta" in map (eta: 5, eta: 6).
diff --git a/spec/libsass-todo-issues/issue_628/input.scss b/spec/libsass-todo-issues/issue_628/input.scss
new file mode 100644
index 0000000000..03ab71c028
--- /dev/null
+++ b/spec/libsass-todo-issues/issue_628/input.scss
@@ -0,0 +1,9 @@
+$map: (
+  alpha: 1,
+  beta: 2,
+  gamma: 3,
+  delta: (
+    eta: 5,
+    eta: 6,
+  ),
+);