A comparison has been made of conformational changes in the DNA molecule during its interaction in solution with different binuclear coordination compounds of platinum [Pt(NH ₃) ₂Cl-R-Pt(NH ₃) ₂Cl]Cl ₂ in cis and trans conformations, which contain cytosine, pyrazine, and carboxypyrazine as the common ligand (R). The influence of concentration of the components, and in particular, of ionic strength of the solution on the complexation process was studied. The influence of the nature of the common ligand, and of cis and trans conformations of coordination compounds on the character of their interaction with DNA was considered. A comparison was made between the structures of DNA complexes with mono-and binuclear compounds with the same set of ligands in the platinum coordination sphere.