The complexing ability of platinum(II) and palladium(II) with various oxygen-sulphur and nitrogen-sulphur donor-containing ligands in various combination of their functional groups have been studied. With this it is found that during complexing not less important role belongs to nature of the primary metal salts, the pH medium, the nature of the solvent and the ratio of reactants. Actual dentaty of thiodiacetic, thiodipropionic acid, mercaptoethanol, and bis-b-hydroxy-ethyl sulphide was determined. Upon finding that during the reaction the cystamine molecule is split into S–S bond and the resulting deprotonated mercamine enters into complexing. In the non-aqueous medium the cleavage of S–S bond does not occur.