The issue taken in the article concerns vessels using gas turbine engines as part of propulsion systems and is an addition to previously conducted research in the field of vessels impact on the environment. The author's purpose was to determine the impact on the natural environment of the frigate's operation, in the aspect of ecological indicators. As part of research, measurements of harmful compounds concentration in the engine exhaust during frigate's cruise with simultaneous registration of engine operation parameters were carried out. The obtained results from the conducted measurements were the subject of a comparative analysis with the engine load values. The comparison of the obtained data made it possible to assign concentration values of particular harmful exhaust compounds to the appropriate engine load conditions during the cruise. On the basis of the analyzes carried out, emission factors for harmful exhaust emissions were determined. These factors allow determining the mass of harmful compounds emitted to the atmosphere from marine gas turbine engines during the operation of the Oliver Hazard Perry frigate.