Nickel-chromium alloys have been in use since early in this century for high temperature applications because of their resistance to oxidation. Since the advent of the gas-turbine engine, more complex alloys capable of maintaining high strength at elevated temperatures have been developed from the simple binary system. These complex alloys were initially mainly strengthened by the precipitation of the Ni3(Ti, Al) phase but more recent alloys have been further strengthened by additions of cobalt, tungsten, molybdenum, niobium, and tantalum. The properties and applications of these alloys are discussed.