In this study, the thermodynamic analysis of a two-stage transcritical CO2 cycle using flash gas by-pass is presented. The gas cooler pressure, the inter-stage pressure and the evaporation temperature of CO2 are selected as variable parameters. The cooling performance and exergetic efficiency variations of the cycle are graphically presented with these parameters. A comparison is presented between the flash gas by-pass two-stage transcritical cycle and the conventional two-stage transcritical cycle and the optimum operating parameters of the cycles are discussed. The importance of flash gas by-pass application is presented for energy and exergy efficiency improvement of two-stage transcritical CO2 cycles.