If you pass a mongodb URI to the connect method, pymongo expects slaveOk to be all lowercase. The documentation at http://www.mongodb.org/display/DOCS/Connections describes the option in camelcase. Pymongo should accept the option camelCase but retain the old functionality for backwards compatibility.

repro:

>>> conn = pymongo.Connection("mongodb://behackett-dt:27019/?connect=direct;slaveOk=true")
>>> conn.port
27018
>>> conn = None
>>> conn = pymongo.Connection("mongodb://behackett-dt:27019/?connect=direct;slaveok=true")
>>> conn.port
27019