The machining characteristics of Al2O3/6061A1 composite using rotary electro-discharge machining with a tube electrode were investigated in this study. Electro-discharge machining was adopted to machine Al2O3/6061A1 composite using a copper tube electrode. The machinability of EDM in terms of the material removal rate; electrode wear rate and surface roughness are evaluated in this paper. The related aspects of this newly developed technique that were investigated include peak currents, pulse durations, volume fraction of Al2O3 reinforced particles, flushing methods, flushing pressures and electrode rotations. Semi-empirical expressions for EDM-drilling were also developed to summarize the effect of machining characteristics such as the material removal rate, electrode wear rate and surface roughness. The peak currents of EDM-drilling and volume fraction of Al2O3 were confirmed to have significant affects on the MRR, EWR and surface roughness. In comparison, the flushing pressure and electrode rotation speed have minor affects on the MRR, EWR and surface roughness. (C) 1999 Elsevier Science S.A. All rights reserved.