In the present experimental study, the performance of a multi-ejector based trans-critical CO2 cooling system is tested at high ambient temperature up to 46°C for a supermarket application with and without internal heat exchanger (IHX) and evaporative cooling. The experimental results indicate that the evaporative cooler capacity reaches a maximum at 10 cm pad thickness. However, a very marginal improvement is observed in terms of COP and PIR (Power Input Ratio) for 15 cm pad thickness. Maximum improvement in COP with IHX and evaporative cooler are 11% and 40% respectively. On the other hand, maximum reduction in the system PIR with IHX and evaporative cooler are 8.5% and 26% respectively. However, marginal enhancement in COP and PIR of 4% and 6% are observed respectively with 15 cm cooling pad thickness. From the study, it is evident that the evaporative cooling for the gas cooler of the CO2 system seems a potential solution to its application at high ambient temperature. © 2019 International Institute of Refrigeration. All rights reserved.