The present work focuses on the fate of two cancerostatic platinum compounds (CPC), cisplatin and carboplatin, as well as of two inorganic platinum compounds, [PtCl 4 ] 2− and [PtCl 6 ] 2− in biological wastewater treatment. Laboratory experiments modelling adsorption of these compounds onto activated sludge showed promising specific adsorption coefficients K D and K OC and Freundlich adsorption isotherms. However, the adsorption properties of the investigated substances were differing significantly. Adsorption decreased following the order cisplatin>[PtCl 6 ] 2− >[PtCl 4 ] 2− >carboplatin. LogK D -values were ranging from 2.5 to 4.3 , logK OC from 3.0 to 4.7.A pilot membrane bioreactor system (MBR) was installed in a hospital in Vienna and fed with wastewater from the oncologic in-patient treatment ward to investigate CPC-adsorption in a sewage treatment plant. During three monitoring periods Pt-concentrations were measured in the influent (3–250μgl −1 Pt) and the effluent (2–150μgl −1 Pt) of the treatment plant using ICP-MS. The monitoring periods (duration 30d) revealed elimination efficiencies between 51% and 63% based on averaged weekly input–output budgets. The derived logK D -values and logK OC -values ranged from 2.4 to 4.8 and from 2.8 to 5.3, respectively. Species analysis using HPLC-ICP-MS proofed that mainly carboplatin was present as intact drug in the influent and – due to low logK D – in the effluent of the MBR.