The complexes [l,2-diam ino-l-(/?-hydroxy)benzyl-l-(methyl, ethyl, and phenyl)]ethane-(dichloro)platinum(II) were synthesized and characterized. The benzylic ^-hydroxy group of the 1,2-diaminoethane ligand leads to good water-solubility o f the complexes. The ligands were synthesized in a Strecker-type reaction, starting from the corresponding /?-methoxybenzylketones. The amino nitriles were reduced to the diamines. Finally, the /?-methoxy groups were converted into hydroxy groups by ether cleavage. For the preparation of the complexes, K 2PtCl4 was added to the ligands. The antitum or activity o f the platinum(II) compounds was tested towards the hum an m am m ary carcinoma cell line M DA-M B 231. The antitum or effect depends on the substituents and increases in the series phenyl, methyl, and ethyl. As a maxi mum, a growth inhibition value of 77% was obtained.