Anti-ship missile (AShMs) is a major threat to ships at sea. The exhaust plume and visible exhaust duct associated with marine gas turbines and diesel engines are major sources of Infrared (IR) radiation of the ship in 3–5 μm wavebands and are excellent targets for IR guided missiles. Therefore, to make a ship stealthier and less vulnerable for enemy detection and attack, it becomes imperative to reduce the temperature of exhaust gas and duct to reduce its IR signature. Globally, various methods are adopted to reduce the temperature of exhaust gas and duct which causes IR signature. NSTL designed eductor–diffuser-type IRSS devices is one of the technologies for reducing temperature of exhaust gas and duct. Such type of devices has been installed on diesel engine exhaust systems of a number of front-line ships. In this system, reduction of temperature is achieved only by addition of cold atmospheric air. For further advancement and enhanced cooling of exhaust gas and duct, water can be injected in proper pattern with suitable water injecting nozzles at various points inside the duct. This paper discusses various methods and motivation for IR signature suppression of ships, existing suppression systems and advanced suppression technologies. The effect of installing IR suppression systems on Lock on range of the ship is also discussed.