A thermodynamic criterion has been applied to determine the reliability of contact metals such as silver, aluminium, gold, chromium, and titanium on bismuth and yttrium based high temperature superconductors (HTSC). The chemical stability is presumed for positive heat of reactions, i.e., ΔHreaction > 0, when a metal reacts with all the possible oxides present in the superconducting material. Based on these calculations, metals for reliable contacts to HTSCs are proposed. © 1994.