Wire electric discharge machine (WEDM) is a non conventional machining method to cut hard to machine material with the help of a wire electrode. High strength low alloy steel (HSLA) is a hard alloy with high hardness and wear resisting property. The purpose of this study is to investigate the effect of parameters on cutting rate for WEDM using HSLA as workpiece and brass wire as electrode. HSLA used in cars, trucks, cranes, bridges, roller coasters and other structures that are designed to handle large amounts of stress. It is seen that cutting rate increases with increase in pulse on time and peak current. Cutting rate decreases with increase in pulse off time and servo voltage. Wire mechanical tension has no significant effect on cutting rate. In order to evaluate the effect of selected process parameters, the Response Surface Methodology (RSM) is used to formulate a mathematical model which correlates the independent process parameters with the desired cutting rate. The central composite rotatable design has been used to conduct the experiments. The analysis of results indicates that the pulse on time, pulse off time, servo voltage and peak current have a significant effect on cutting rate.