Electrochemical Machining (ECM) is an important advanced machining process useful to obtain good quality finish with a stress-free and crack free machined surface. Machining performance of the process is independent of the hardness of the material. Objective of this study is to assess the effect of process parameters of the ECM on material removal rate (MRR) and surface roughness (SR) during machining of EN-31 alloy steel. The EN-31 alloy steel is widely used in the manufacturing industry for making plastic molding dies, gears, automobile parts, etc. The machining experiments have been conducted according to the design of experiments based on Central Composite Face Centered Design (CCFCD) with three independent input parameters – voltage, electrolyte concentration and electrolyte flow rate, and two response parameters – material removal rate (MRR) and surface roughness (SR). Response Surface Methodology (RSM) has been used to develop the empirical relationship between the response parameters and the input process parameters. Optimization has been carried out to maximize the MRR and minimize the SR using desirability function.