Thin films of nickel manganite were deposited onto different substrates by means of electron beam evaporation from a powder source of the compound and annealed at 500 and 600 degrees C for 30 min. in air, oxygen or nitrogen to study the effects of annealing temperature and atmosphere on the structure and properties of grown thin films. X-ray diffraction and infrared spectroscopy were used to confirm the formation of nickel manganite; the integrity of the films and their elemental compositions were assessed using a scanning electron microscope equipped with an energy dispersive X-ray analyser. Resistance-temperature characteristics were measured between room temperature and 600 K. The values of thermistor constant (B) were found to be dependent on the post growth treatments; annealing in O-2 or air yielded the lowest values of B similar to 2000-3000 K, while as-deposited and N-2 annealed layers had values of B similar to 5000-6500 K.