Résumé : Four compounds of the type [(o‐RNH‐C6H4COO)(CH3CH2CH2CH2)2Sn]2O and [(o‐CH3NH‐C6H4COO)(CH3)2Sn]2O have been prepared, characterized by 1H, 13C, 119Sn NMR, and by Mössbauer and mass spectrometry. They have been tested in vitro against two human tumour cell lines, nl. MCF‐7 (mammary tumour) and WiDr (colon carcinoma), and found to score slightly better than cis‐platin but markedly less than other cytostatic agents. Copyright © 1991 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim