diff --git a/HISTORY.rst b/HISTORY.rst
index 5f1b6a3a..2bf6e11d 100644
--- a/HISTORY.rst
+++ b/HISTORY.rst
@@ -1,7 +1,13 @@
 History
 -------
 
-0.6.5 (2011-10-19)
+0.6.6 (2011-10-19)
+++++++++++++++++++
+
+* Session parameter bugfix (params merging)
+
+
+0.6.5 (2011-10-18)
 ++++++++++++++++++
 
 * Offline (fast) test suite.
@@ -17,11 +23,13 @@ History
 * New ``r.faw`` interface for advanced response usage.*
 * Automatic expansion of parameterized headers
 
+
 0.6.3 (2011-10-13)
 ++++++++++++++++++
 
 * Beautiful ``requests.async`` module, for making async requests w/ gevent.
 
+
 0.6.2 (2011-10-09)
 ++++++++++++++++++
 
diff --git a/requests/core.py b/requests/core.py
index 9e518357..79449801 100644
--- a/requests/core.py
+++ b/requests/core.py
@@ -12,8 +12,8 @@ This module implements the main Requests system.
 """
 
 __title__ = 'requests'
-__version__ = '0.6.5'
-__build__ = 0x000605
+__version__ = '0.6.6'
+__build__ = 0x000606
 __author__ = 'Kenneth Reitz'
 __license__ = 'ISC'
 __copyright__ = 'Copyright 2011 Kenneth Reitz'
diff --git a/requests/sessions.py b/requests/sessions.py
index 4e7022d6..9226a545 100644
--- a/requests/sessions.py
+++ b/requests/sessions.py
@@ -49,7 +49,7 @@ def merge_kwargs(local_kwarg, default_kwarg):
 class Session(object):
     """A Requests session."""
 
-    __attrs__ = ['headers', 'cookies', 'auth', 'timeout', 'proxies', 'hooks']
+    __attrs__ = ['headers', 'cookies', 'auth', 'timeout', 'proxies', 'hooks', 'params']
 
 
     def __init__(self,
@@ -58,7 +58,8 @@ class Session(object):
         auth=None,
         timeout=None,
         proxies=None,
-        hooks=None):
+        hooks=None,
+        params=None):
 
         self.headers = headers or {}
         self.cookies = cookies or {}
@@ -66,6 +67,7 @@ class Session(object):
         self.timeout = timeout
         self.proxies = proxies or {}
         self.hooks = hooks or {}
+        self.params = params or {}
 
         # Set up a CookieJar to be used by default
         self.cookies = cookielib.FileCookieJar()
diff --git a/test_requests.py b/test_requests.py
index dbfe527d..a34e2338 100755
--- a/test_requests.py
+++ b/test_requests.py
@@ -468,5 +468,33 @@ class RequestsTestSuite(unittest.TestCase):
         self.assertEqual(r2.status_code, 200)
 
 
+    def test_session_persistent_params(self):
+
+        params = {'a': 'a_test'}
+
+        s = Session()
+        s.params = params
+
+        # Make 2 requests from Session object, should send header both times
+        r1 = s.get(httpbin('get'))
+        assert params['a'] in r1.content
+
+
+        params2 = {'b': 'b_test'}
+
+        r2 = s.get(httpbin('get'), params=params2)
+        assert params['a'] in r2.content
+        assert params2['b'] in r2.content
+
+
+        params3 = {'b': 'b_test', 'a': None, 'c': 'c_test'}
+
+        r3 = s.get(httpbin('get'), params=params3)
+
+        assert not params['a'] in r3.content
+        assert params3['b'] in r3.content
+        assert params3['c'] in r3.content
+
+
 if __name__ == '__main__':
     unittest.main()