Abstract: An oil supply system for a gas turbine comprises an oil feeding device, a water feeding device and a blow-off device, The oil feeding device comprises a fuel distributor connected to an oil supply line and delivering oil through primary and secondary oil conduits and to the combustion chambers of the turbine. The water feeding device comprises a water supply line connected to a distributor delivering primary and secondary water through conduits to the combustion chambers. The blow-off device comprises an air supply line split into two supply branch lines, two closed circular pipes connected to the supply branch lines by connection valves, and primary and secondary air conduits connected to the closed circular pipes for delivering air to the nozzles of the combustion chamber. To ensure a gentle oil firing operation of the gas turbine meeting the requirement of low emission values, the oil and water feeding devices comprise a secondary distributor connected to the oil and water, respectively.