Two established human testicular cancer cell lines were used in a mouse xenograft model to assess the antitumour activity of 15 anticancer agents. Line H 12.1 was highly sensitive to cisplatin, bleomycin and vinblastine, resembling non-pretreated testicular tumours, whereas line H 23.1 showed resistance to cisplatin and vinblastine, comparable to tumours with acquired or intrinsic drug resistance. In line H 12.1 several drugs were highly active, including cyclophosphamide, ifosfamide, nimustine and vincristine; carmustine, vindesine, doxorubicin, epidoxorubicin, pirarubicin, mitoxantrone, carboplatin and iproplatin had only moderate activity. In line H 23.1 only cyclophosphamide, ifosfamide, nimustine, vincristine and bleomycin had antitumour activity. These two cell lines represent a useful model for preclinical evaluation of new agents with presumed activity in testis cancer. © 1990.