I am using Server 2012 with Visual 2012/13 and writing a mongo c# application to be able to create DB's on the fly via a web application. It would be good to be able to create the DB and the User and assign the role at the same time. You can do this via the mongo.exe command line tool so I assume that the functionality should be in the driver also. YOu can see this in the db.adduser function on this page. http://docs.mongodb.org/manual/reference/method/db.addUser/