The background of the development of fire resistant fluids for Navy hydraulic and compressed air systems is described. Experiences in the use of such fluids and factors considered in their selection and evaluation are discussed. While progress has been made, more research and development effort is required. Present programs to achieve superior fire resistant fluids are described. Cooperation of industry laboratories is needed for solving some of the problems attendant to the development of optimum fire resistant fluids for hydraulic and high pressure air systems.