The purpose of this study was to assess cytotoxic effect of four new platinum compounds on B16 and CIS91 melanoma cells in vitro. The following complexes were tested: (2) Tetrachlorobis (5,7-dimethyl-1,2,4-triazol [1,5alpha] pirymidine) platinum (IV), (3) trans-dichloro (dimethylsulfoxide) (5,7-dimetyl-1,2,4-triazol-[1,5alpha] pirymidine) platinum(II), (4) cis-dichloro(dimethylsulfoxide)(1-beta-D-ribofuranosyl-1,2,4-triazol-3-carboxamide)platinum(II), (5) chloro(dimethylsulfoxide)(1-beta-D-ribofuranosyl-1,2,4-triazol-3-carboxamide)platinum(II). We can conclude, that Pt-dmtp (2) represented the best cytotoxic properties in the group of four tested platinum compounds, Pt-rib-1 (4) has also a good cytotoxic properties although its IC50 value is quite high. We suppose that cytotoxic and soluble properties ot Pt-dmtp and Pt-rib-1 could be modified and improved.