Whereas platinum compounds are already clinically used as anticancer agents, tin compounds exhibiting high enough antitumour activity have not yet been found to enter the clinical phase. This is paradoxical with the observation that 50% of the tested compounds showed some activity, which is an abnormally high percentage. This is probably due to the fact that research of this type with tin compounds started more recently than with platinum compounds and that almost exclusively known compounds coming from laboratories working in the field of organotin compounds have been blindly tested. Some research directed towards the development of organotin compounds with some biologically favourable properties, for instance derivatives with hydrophilic or lipophilic, or with increased bio-availability characteristics, has started only recently. We thought that was now the appropriate time to bring together experts from different disciplines (biochemists, pharmacologists, organotin chemists, oncologists, etc.) working in the field of tin-based antitumour drugs, to contribute to the critical assessment of existing knowledge in this new important topic, to identify the directions for future research and to promote close working relations between the different countries and professional experiences gathered in this workshop.