This paper presents the results of experimental studies carried out to conduct a comprehensive investigation on the influence of Electrical Discharge Machining (EDM) input parameters on the characteristics of the EDM process. The studied process characteristics included machining features, embracing material removal rate, tool wear ratio, and arithmetical mean roughness, as well surface integrity characteristics comprised of the thickness of white layer and the depth of heat affected zone of AISI H13 tool steel as workpiece. The experiments performed under the designed full factorial procedure, and the considered EDM input parameters included pulse on-time and pulse current. The results of this study could be utilized in the selection of optimum process parameters to achieve the desired EDM efficiency surface roughness, and surface integrity when machining AISI H13 tool steel. (C) 2011 Journal of Mechanical Engineering. All rights reserved.