Copper nitride (Cu3N) thin films were deposited on glass substrates by reactive radio-frequency (rf) magnetron sputtering from a metal copper target in a nitrogen/argon atmosphere. The deposition rate of the films gradually decreased and excessive nitrogen was added to the films as nitrogen partial pressure increased. The color of the deposited films was a reddish dark brown. The Cu3N films obtained by this deposition method were strongly textured with crystal direction[100]. The grain size of the polycrystalline films ranged from 15 to 30 nm. The resistivity and the optical energy gap of the films were found to be change with the nitrogen content.