The changes in structure and chemical composition of gold coatings after thermal treatment in dependence on the composition of metallic layers has been studied by transmission electron microscopy, scanning electron microscopy and X-ray diffraction (XRD). An electrodeposited gold coating on Ti as well as on Fe-Ni/Cu and Ni-B/Cu systems had no observable changes in phase composition and structure after thermal treatment of 200 h at 150-200 degrees C. Spontaneous growth of gold crystal whiskers were observed on the gold coating on a Ti substratum (50-100 h, 350 degrees C). There were changed friable structures in some places. XRD data testify a presence of Au2Ti and AuTi3. A changed structure containing big grains developed in some places on the gold coating of the system Au/Fe-Ni/Cu after thermal treatment (50 h, 350 degrees C). Nickel diffusion and the presence of intermetallic AuCn in the gold coating was also observed, The gold coating of the system Au/Ni-B/Cu remains stable with respect tb structure and chemical purity. The electrodeposited Ni-B layer (B, 4-8 wt.%; C, 3-7 and 10(-2) wt.% in dependence of the technique of electrodeposition) is amorphous. The gold coating on a Ni-B substratum had no observable changes in structure after a thermal treatment of 200 h, 350 degrees C.