A performance of fixed ejectors installed in a multi-ejector module in a CO2 refrigeration system is discussed in this paper. To analyse the module operation, 3-D ejector models including the inlet and outlet collecting ducts were taken into consideration. The tests were performed for four vapour and two liquid ejectors of different size that compose the multi-ejector pack. The testing modes included the serial and parallel work of the fixed units. All the numerical simulations were performed using the validated Homogeneous Equilibrium Model (HEM) implemented on the ejectorPL computational tool for typical transcritical parameters at the motive nozzle port. The results showed that multi-ejector pack provides high and stable performance of all the installed ejectors over the entire range of the considered operating conditions for supermarket applications.