Résumé : Four steroidal organotin compounds have been prepared and compared in vitro with a parent steroid and two model compounds in a series of human tumor cell lines. The organotin steroids (compounds 1 and 2) showed promising in vitro activity. Another compound with important characteristics in terms of bond angles and stereochemistry (compound 3) was a highly effective antitumor agent. This compound may serve as a model for further investigation on the structure-activity relationship in antitumor organotin compounds. © 1992.