A cryogenic balloon catheter system includes an inflatable balloon, a handle assembly and a pressure sensor. The inflatable balloon has a balloon interior. The pressure sensor senses a balloon pressure within the balloon interior. In various embodiments, the pressure sensor can be positioned within the balloon interior, within the handle assembly and/or between the inflatable balloon and the handle assembly. The cryogenic balloon catheter system also includes a controller that receives a sensor output from the pressure sensor. The controller can control injection of a cooling fluid to the balloon interior and/or removal of the cooling fluid from the balloon interior based upon the sensor output. The cryogenic balloon catheter system can also include an injection proportional valve, an exhaust proportional valve, an injection flow sensor and/or an exhaust flow sensor.