The electrical discharge machining is an exceptional procedure for machining complex shapes into electric conductor materials, mainly for those of high hardness, difficult of machining by traditional processes. At each discharge, a crater is formed in the material and a small crater is formed in the electrode. From every molten material produced in each discharge, only 15%, or less is removed through the dielectric liquid. The remaining of molten material solidifies forming a wrinkled surface. The characteristics of the obtained surface, as overlap of craters, globules of sullage, "chimneys", bubbles (formed when trapped gases are released through the resolidified material), are revealed through an analysis by scanning electron microscopy. The proposed study aimed to examine the effect of several dielectric fluids, on the surface topography and material removal rate, in workpiece of high speed steel (ABNT M2), during the electrical discharge machining.3312730Newman, S.T., State of the art electrical discharge machining (EDM) (2003) International Journal of Machine Tools and Manufacture, 43 (13), pp. 1287-1300Kumar, S., Singh, R., Singh, T.P., Sethi, B.L., Surface modification by electrical discharge machining: A review (2009) Journal of Materials Processing Technology, 209 (8), pp. 3675-3687Mahardika, M., Tsujimoto, T., Mitsui, K., A new approach on the determination of ease of machining by EDM processes (2008) International Journal of Machine Tools and Manufacture, 48 (5), pp. 746-760Rodrigues, J.R.P., Cruz, C., Franco, S.D., Assunção, W., Avaliação da geração de microtrincas do aço rápido ABNT M2 no processo EDM com adição de SiC (2008) Acta Scientiarum. Technology, 30 (2), pp. 173-179Simao, J., Lee, H.G., Aspinwall, D.K., Dewes, R.C., Aspinwall, E.M., Workpiece surface modification using electrical discharge machining (2003) International Journal of Machine Tools and Manufacture, 2 (43), pp. 121-128Singh, S., Maheshwari, S., Pandey, P.C., Some investigations into the electric discharge machining of hardened tool steel using different electrode materials (2004) Journal of Materials Processing Technology, 12 (149), pp. 272-277Tsai, K.M., Wang, P.J., Semi-empirical model of surface finish on electrical discharge machining (2001) International Journal of Machine Tools and Manufacture, 41 (3), pp. 1455-1477Wang, Y.G., Zhao, F.L., Wang, H., A study on the effect of powder on surface quality in EDM finishing (2007) International Journal of Computer Applications in Technology, 29 (2-4), pp. 225-228