Abstract: Interaction of trans-[Pt(NH₃)₃Cl_{213C NMR. The formation of a series of complexes and the site of complexation of nucleosides (or nucleotide) to trans-[Pt(NH3)2Cl2] in the reaction systems were ascertained. On the basis of the results obtained, a possible reasoning of different behaviours of cis-, trans-[Pt(NH3)2 Cl2] in antitumour action was discussed.}