A cell line, designated as RMG-V, was established from a patient with clear cell adenocarcinoma of the ovary. The cell line has grown without interruption and has been propagated continuously by serial passaging (more than 36 times) over 5 years. The cells are spindle-shaped, display neoplastic and pleomorphic features, and grow in a jigsaw puzzle-like arrangement while forming monolayers without contact inhibition. These cells proliferate rapidly, and the population doubling time is about 15.5 hours. The number of chromosomes ranges between 77 and 85, with a modal number of 83.