diff --git a/libmproxy/flow.py b/libmproxy/flow.py
index b22be3f95..44dc57ae4 100644
--- a/libmproxy/flow.py
+++ b/libmproxy/flow.py
@@ -735,6 +735,8 @@ class Response(HTTPMsg):
         )
         if self.content:
             headers["Content-Length"] = [str(len(self.content))]
+        elif 'Transfer-Encoding' in self.headers:
+            headers["Content-Length"] = ["0"]
         proto = "HTTP/%s.%s %s %s"%(self.httpversion[0], self.httpversion[1], self.code, str(self.msg))
         data = (proto, str(headers))
         return FMT%data
diff --git a/test/test_server.py b/test/test_server.py
index 182b969f4..2c94b9dff 100644
--- a/test/test_server.py
+++ b/test/test_server.py
@@ -143,7 +143,18 @@ class TestHTTP(tservers.HTTPProxTest, CommonMixin, AppMixin):
         req = p.request("get:'http://foo':h':foo'='bar'")
         assert req.status_code == 400
 
-
+    def test_empty_chunked_content(self):
+        """
+        https://github.com/mitmproxy/mitmproxy/issues/186
+        """
+        connection = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
+        connection.connect(("127.0.0.1", self.proxy.port))
+        spec = '301:h"Transfer-Encoding"="chunked":r:b"0\\r\\n\\r\\n"'
+        connection.send("GET http://localhost:%d/p/%s HTTP/1.1\r\n"%(self.server.port, spec))
+        connection.send("\r\n");
+        resp = connection.recv(50000)
+        connection.close()
+        assert "content-length" in resp.lower()
 
 class TestHTTPAuth(tservers.HTTPProxTest):
     authenticator = http_auth.BasicProxyAuth(http_auth.PassManSingleUser("test", "test"), "realm")