Experiments have been performed to measure the total pressure lossof the flow through a two-dimensional turbine cascade with “coolant” injection from a single row of holes on the suction or pressure side of the blades. The tests were performed in a low speed tunnel. Air and carbon dioxide were used as secondary fluids, the latter to provide a large density difference between the gas in the mainstream and the injected gas. Both gas streams had the same temperature. The measured pressure loss is in good agreementwith analytical predictions based on a model introduced by Hartsel. The results thus provide information which can be incorporated in a program which predicts the influence of injection on the aerodynamic efficiency of a gas turbine.