Using vacuum−deposition techniques, a thin film thermistor has been developed. The device consists of a tin selenide sensing material, platinum leads, and quartz encapsulation deposited on a 1/4 mil kapton substrate. The resistance of a typical sensor shows increases of 2 1/2 orders of magnitude for a corresponding temperature decrease from 30 to −130°C. The room temperature resistance and resistance vs temperature dependence of the sensor can be controlled by a proper choice of the deposition parameters and the device configuration.