Analysis of an endoreversible two-stage cascade cycle has been implemented and optimum intermediate temperature for maximum exergy and refrigeration effect have been obtained analytically. Further, the heat reservoir temperatures has been optimised independently. A comprehensive numerical model of a transcritical CO 2 –C 3 H 8 cascade system was developed with intent to verify the theoretical results. It is seen that the simulation results agree well for optimal T L but deviate modestly from the theoretical optimum of T H . It has also been observed that system performance improves as T H increases and unlike theoretical predictions, no optimal T H is present within feasible working temperatures.