Vortex tube is a device that produces cold and hot air simultaneously from the source of compressed air. In this work an attempt has been made to investigate the effect of three controllable input variables namely diameter of the orifices, diameter of the nozzles and inlet pressure over the temperature difference in the cold side as output using Response Surface Methodology (RSM). Experiments are conducted using central composite design with three factors at three levels. The influence of vital parameters and interaction among these are investigated using analysis of variance (ANOVA). The proposed mathematical model in this study has proven to fit and in line with experimental values with a 95% confidence interval. It is found that the inlet pressure and diameter of nozzle are significant factors that affect the performance of vortex tube.