This work aimed at studying the effect of a Ti interlayer and the alloying with carbon and nitrogen of W-S-C(N) films on the mechanical and tribological proper-ties. The W-S-C and W-S-N films were deposited by r.f. magnetron reactive sputtering with CH4 or N-2 as reactive gases and analysed by high resolution electron microscopy techniques. The hardness showed an improvement with the addition of the alloying element, which was attributed to the densification of the morphology, the decrease of the grain size, and the precipitation of new phases harder than WS2. The formation of either TiC or TiN at the interface between the Ti interlayer and the W-S-C(N) films promoted the enhancement of adhesion in the alloyed films. These improvements led to an enhanced tribological behaviour, in particularly the towering of the wear coefficients. (c) 2005 Elsevier B.V. All rights reserved.