Polystyrene-carbon nanotubes (PS-CNTs) nanocomposites with 0-4.0 wt.% content have been prepared successfully by means of in situ polymerization process. The microhardness of PS-CNTs nanocomposites was measured. It was found that CNTs effectively increased the microhardness of the nanocomposites. The tribological behaviors of the nanocomposites were investigated by a friction and wear tester under dry conditions. Comparing with pure PS, PS-CNTs nanocomposites showed not only higher wear resistance but also smaller friction coefficient. CNTs could dramatically reduce the friction and improve the wear resistance behaviors of the nanocomposites. The mechanisms of the significant improvements on the tribological properties of the PS-CNTs nanocomposites were also discussed. (c) 2005 Published by Elsevier B.V.