Thin films of tungsten carbide have been deposited by rf magnetron sputtering in the substrate temperature range of 200–500 °C. A mixture of mono-, di-, and tricarbides are formed at low temperatures but a single phase monocarbide is formed at high temperatures. The films consist of randomly shaped granular surface of grain size 400–500 Å. Fractured cross section of the films shows a columnar structure consisting of fine columns of width 300 Å. The interface formed between the film and substrate shows a gradual variation of the concentration of elements over a thickness of 250 Å in thin films. The thicker films show a large interfacial region, and is attributed to a loss in depth resolution due to sputter etching of the film.