The synthesis and in vitro cytotoxicity ofcis -(glycolato-O,O )[2-substituted-(4R,5R)-4,5-bis(aminomethyl)-1,3-dioxolane] platinum(II) are described. Among them,cis -(glycolato-O,O )[(4R,5R)-4,5-bis(aminomethyl)-2,2-diethyl-1,3-dioxolane]pl atinum(II) (26) was found to be almost equally cytotoxic to cisplatin against two human non-small cell lung cancer cell lines, PC-9 and PC-14, and two human stomach cancer cell lines, MKN-45 and KATO III.