A cell line, IGROV1, originating from an ovarian carcinoma of a 47-year-old woman was established in tissue culture and in nude mice. Maintained in monolayer cultures, IGROV1 cells exhibited a 20-h doubling time and highly tumorigenic properties. The s.c. injection of 2 X 10(6) cultured cells into nude mice gave rise to fast growing tumors, while the i.p. route induced a peritoneal carcinomatosis with ascites which killed the animals in 2 months. The epithelial morphology of IGROV1 cells was retained during in vitro and in vivo passages, as judged by both the light and the electron microscopes. Two cytogenetic markers characterize IGROV1 cells: a paracentric inversion of chromosome 3, and a translocation between chromosomes 2 and 5. The constitutional karyotype of the patient was normal. These characteristics make the IGROV1 cell line a suitable experimental model for the treatment of human ovarian carcinomas and for biological studies of human solid tumors.