diff --git a/isso/wsgi.py b/isso/wsgi.py
index 9f7454a..19690f6 100644
--- a/isso/wsgi.py
+++ b/isso/wsgi.py
@@ -34,7 +34,7 @@ class CORSMiddleWare(object):
             else:
                 origin = host.rstrip("/")
 
-            headers.append(("Access-Control-Allow-Origin", origin.encode("latin-1")))
+            headers.append(("Access-Control-Allow-Origin", origin))
             headers.append(("Access-Control-Allow-Headers", "Origin, Content-Type"))
             headers.append(("Access-Control-Allow-Credentials", "true"))
             headers.append(("Access-Control-Allow-Methods", "GET, POST, PUT, DELETE"))
diff --git a/specs/test_cors.py b/specs/test_cors.py
index e69de29..eea4e4c 100644
--- a/specs/test_cors.py
+++ b/specs/test_cors.py
@@ -0,0 +1,52 @@
+
+from werkzeug.test import Client
+from werkzeug.wrappers import Response
+
+from isso.wsgi import CORSMiddleWare
+
+
+def hello_world(environ, start_response):
+    start_response('200 OK', [('Content-Type', 'text/html')])
+    return ["Hello, World."]
+
+
+def test_simple_CORS():
+
+    app = CORSMiddleWare(hello_world, hosts=[
+        "https://example.tld/",
+        "http://example.tld/",
+        "http://example.tld",
+    ])
+
+    client = Client(app, Response)
+
+    rv = client.get("/", headers={"ORIGIN": "https://example.tld"})
+
+    assert rv.headers["Access-Control-Allow-Origin"] == "https://example.tld"
+    assert rv.headers["Access-Control-Allow-Headers"] == "Origin, Content-Type"
+    assert rv.headers["Access-Control-Allow-Credentials"] == "true"
+    assert rv.headers["Access-Control-Allow-Methods"] == "GET, POST, PUT, DELETE"
+    assert rv.headers["Access-Control-Expose-Headers"] == "X-Set-Cookie"
+
+    a = client.get("/", headers={"ORIGIN": "http://example.tld/"})
+    assert a.headers["Access-Control-Allow-Origin"] == "http://example.tld"
+
+    b = client.get("/", headers={"ORIGIN": "http://example.tld"})
+    assert a.headers["Access-Control-Allow-Origin"] == "http://example.tld"
+
+    c = client.get("/", headers={"ORIGIN": "http://foo.other/"})
+    assert a.headers["Access-Control-Allow-Origin"] == "http://example.tld"
+
+
+def test_preflight_CORS():
+
+    app = CORSMiddleWare(hello_world, hosts=["http://example.tld"])
+    client = Client(app, Response)
+
+    rv = client.open(method="OPTIONS", path="/", headers={"ORIGIN": "http://example.tld"})
+    assert rv.status_code == 200
+
+    for hdr in ("Origin", "Headers", "Credentials", "Methods"):
+        assert "Access-Control-Allow-%s" % hdr in rv.headers
+
+    assert rv.headers["Access-Control-Allow-Origin"] == "http://example.tld"