Tungsten-carbon thin films have been deposited by reactive (Ar + C6H6) DC magnetron sputtering onto various substrates. Deposition onto glass, monocrystalline silicon, tantalum and stainless steel at room temperature yielded W-C films, having XRD patterns corresponding to the structure of heavily disordered W2C or WC1-x carbides. The samples deposited upon the Au or Cu foils were nanocrystalline cubic WC1-x with the grain size of 2.9 nm. Disordered tungsten-carbon films were stable up to 1200 degrees C, Microhardness of the films with disordered W2C phase was about 5-6 GPa while that of the films with disordered WC1-x phase was about 17 GPa. The characteristics of films can be understood considering the effects of the incorporation of free carbon and/or carbon-hydrogen fragments into the tungsten carbide layer.