The microstructure and wear of an A-356 aluminum alloy superficially modified by laser alloying were studied. A 2000-W Nd-YAG laser was employed for alloying a powder composed of 96 wt.% WC, 2 wt.% Ti and 2 wt.% Mg at different traverse velocities of 100, 200, 300 and 400 cm min(-1). Optical (OM) and Scanning Electron Microscopy (SEM) were used to examine the morphology and microstructure of the sample surfaces and laser melting zones (LMZ). Wear properties were studied under a load of 5 N by using the ball-on-disc tribometer. The static partners were balls of 6 mm in diameter made of 52100 steel. Friction coefficients as well as wear volumes are reported. X-Ray mapping of the wear surfaces was used to establish the wear mechanism. It was shown that, under the conditions in which the wear test was performed, laser alloying of the sand cast Al-356 alloy with WC particles has improved considerably the wear resistance of the substrate. The WC particles serve as load-carrying particles and have a severe abrasive action on the steel counterpart contributing to the steel transference onto the laser treated surface. As the particle size of these carbides decreases, due to a higher interaction time of the laser beam with the substrate, the wear mechanism changes and the aluminum matrix takes part in the transference process, i.e. some of the material from the laser-treated surface transfers to the steel ball. Even in this latter case, the laser-treated surface has a better wear resistance than the substrate. The results were correlated to the roughness, morphological and microstructural characteristics in each case.