This paper reports, for the first time, an analysis of the effect of High Current Pulsed Electron Beam (HCPEB) on a Mg alloy. The AZ31 alloy was HCPEB treated in order to see the potential of this fairly recent technique in modifying its wear resistance. For the 2.5 J/cm(2) beam energy density used in the present work, the evaporation mode was operative and led to the formation of a "wavy" surface and the absence of eruptive microcraters. The selective evaporation of Mg over Al led to an Al-rich melted surface layer and precipitation hardening from the over saturated solid solution. Due to the increase in hardness of the top surface layer, the friction coefficient values were lowered by more than 20% after the HCPEB treatments, and the wear resistance was drastically (by a factor of 6) improved. The microhardness of the HCPEB samples was also increased significantly down to a depth of about 500 mu m, far exceeding the heat-affected zone (about 40 mu m). This is due to the effect of the propagation of the shockwave associated with this HCPEB treatment. (c) 2005 American Vacuum Society.