Four continuous cell lines were established from 15 biopsies of human squamous carcinomas of the uterine cervix, two from women less than 35 years old. All four lines grew as adherent monolayers and had epitheloid morphology. All required initial 3T3 feeder layer support and hydrocortisone and insulin for growth and have now been grown in vitro for at least 12 months. The individual lines possessed unique isozyme patterns and were distinct from the HeLa cell line. All were tumorigenic in nude mice. In vitro colony forming efficiencies ranged from 2 to 30% in a monolayer anchorage dependent assay but were only from 0.0025 to 0.6% when assayed in soft agar. The lines were all aneuploid with mean chromosome numbers ranging from 71 to 75. Analysis of intermediate filament expression showed that all lines were positive for cytokeratin expression and two were positive for vimentin expression. These low-passage cell lines represent a panel of new in vitro models of carcinoma of the cervix. They should be useful for the investigation of chemosensitivity, of the involvement of human Papillomavirus in this disease, and as models of squamous cell differentiation.