In this paper an experimental investigation was carried out to optimize the performance characteristics (surface roughness and Metal removal rate) simultaneously in hot machining process. The experiments were conducted on 15-5PH stainless steel using K313 carbide tool based on Taguchi L27 orthogonal array design. The work-piece material was heated using oxy-acetylene gas flame which is the cost effective method compare to other heating technique used in hot machining process. Analysis of variance is performed to get the contribution of each parameter on the performance characteristics and it was observed that cutting speed is most significantly affect the performance characteristics compare to feed, depth of cut and temperature. The optimal set of process parameters were found to be cutting speed at 31 m/min, feed rate at 0.4mm/rev, depth of cut at 0.4mm and workpiece temperature at 400°C to maximize material removal rate and minimize surface roughness.