Martensitic transformation temperatures, M-s, M-f, A(s) and A(f), of an annealed Au-47.5 at.% Cd-0.75 at.% Cu alloy were obtained by X-ray diffraction method and electrical resistivity measurement. Four sets of the four values depend on the different X-ray wavelengths and the methods. The incubation time was observed during the isothermal holding between M-s and M-f, from the time dependence of electrical resistivity when the Kapton foil was used as the thermal insulation between the sample and the holder. The incubation time becomes longer when the temperature is close to M-s.