diff --git a/src/client/Python/msrest/msrest/pipeline.py b/src/client/Python/msrest/msrest/pipeline.py
index a376139a22f1a..04410ec19ca37 100644
--- a/src/client/Python/msrest/msrest/pipeline.py
+++ b/src/client/Python/msrest/msrest/pipeline.py
@@ -27,6 +27,10 @@
 import functools
 import json
 import logging
+try:
+    from urlparse import urlparse
+except ImportError:
+    from urllib.parse import urlparse
 
 import requests
 from requests.packages.urllib3 import Retry
@@ -195,6 +199,14 @@ def format_parameters(self, params):
 
         :param dict params: A dictionary of parameters.
         """
+        query = urlparse(self.url).query
+        if query:
+            self.url = self.url.partition('?')[0]
+            existing_params = {
+                p[0]: p[-1]
+                for p in [p.partition('=') for p in query.split('&')]
+            }
+            params.update(existing_params)
         query_params = ["{}={}".format(k, v) for k, v in params.items()]
         query = '?' + '&'.join(query_params)
         self.url = self.url + query
diff --git a/src/client/Python/msrest/readme.rst b/src/client/Python/msrest/readme.rst
index 3ddf58e590307..214f6f7b5ae18 100644
--- a/src/client/Python/msrest/readme.rst
+++ b/src/client/Python/msrest/readme.rst
@@ -15,6 +15,13 @@ To install:
 Release History
 ---------------
 
+2016-xx-xx Version xxxxx
+++++++++++++++++++++++++
+
+**Bugfixes**
+
+- Allow url of ClientRequest to have parameters (https://github.com/Azure/autorest/issues/1217)
+
 2016-05-25 Version 0.4.0
 ++++++++++++++++++++++++
 
diff --git a/src/client/Python/msrest/test/unittest_pipeline.py b/src/client/Python/msrest/test/unittest_pipeline.py
index dd757191befb5..cb5a1e7fb7a1f 100644
--- a/src/client/Python/msrest/test/unittest_pipeline.py
+++ b/src/client/Python/msrest/test/unittest_pipeline.py
@@ -167,6 +167,17 @@ def test_request_data(self):
         self.assertEqual(request.data, json.dumps(data))
         self.assertEqual(request.headers.get('Content-Length'), 17)
 
+    def test_request_url_with_params(self):
+
+        request = ClientRequest()
+        request.url = "a/b/c?t=y"
+        request.format_parameters({'g': 'h'})
+
+        self.assertIn(request.url, [
+            'a/b/c?g=h&t=y',
+            'a/b/c?t=y&g=h'
+        ])
+
 class TestClientResponse(unittest.TestCase):
 
     class Colors(Enum):
diff --git a/src/client/Python/msrest/tox.ini b/src/client/Python/msrest/tox.ini
index 52dff903bbda4..7939eaafef286 100644
--- a/src/client/Python/msrest/tox.ini
+++ b/src/client/Python/msrest/tox.ini
@@ -7,7 +7,7 @@ changedir=test
 commands=
     coverage run -m unittest discover -s . -p unittest*.py -t .. -v
     coverage report --fail-under=40 --omit=unittest*,*.tox*.py
-    flake8 .. --exclude=unittest*.py,doc --statistics
+    flake8 .. --exclude=unittest*.py,doc,env --statistics
 
 [testenv:py27]
 deps=