Human ovarian carcinomas (HOC) were established s.c. and i.p. in nude mice and the biological characteristics were investigated for 4 xenografts. HOC8 and HOC18, derived respectively from a primary tumor of the ovary and a pleural effusion (from 2 different patients) were established s.c. in nude mice. HOC10 and HOC22, derived from the ascites of 2 patients, were directly established as ascites after i.p. injection in nude mice. The s.c. and i.p. growth behavior of the 4 HOC lines was investigated. HOC18, HOC8 and HOC22 cells produced progressively growing tumor after s.c. injection but HOC10 ascites would not grow s.c. The cell suspension derived from HOC18 only produced carcinomatosis upon i.p. injection, while HOC8 cells produced both ascites and carcinomatosis. The 2 ascites HOC10 and HOC22 produced ascites in nude mice, but only HOC22 formed i.p. carcinomatosis. Histopathological characteristics of the patients' primary tumors persisted in nude mice, regardless of the site of tumor implantation. DNA histograms of the xenografts closely matched the patients' tumors and remained stable at different passages. Cisplatin, adriamycin and cyclophosphamide given i.v. were tested against HOC8 and HOC18 growing s.c. and HOC22 and HOC10 growing i.p. HOC8 showed a significant response to DDP and almost no sensitivity to ADR and CTX. HOC18 showed only moderate growth delay with all 3 drugs. Mice bearing HOC10 and HOC22 ascites had a prolonged survival time after DDP and ADR treatment.