We describe a new and unique gastric carcinoma cell line (LIM1839) derived from a young Caucasian male with rapidly progressing disease. The cell line grows with a pleomorphic morphology and has been in continuous culture for more than 3 years. The cells cannot be cloned in semi-solid agar or grown in nude mice despite numerous attempts. The karyotype of the cultured cells is highly abnormal with a large number of structural and numerical changes. Some chromosomes are dicentric and this feature has persisted in this culture. The cells express one of the small-intestinal dipeptidases, aminopeptidase N, but do not express dipeptidyl peptidase IV or the disaccharidases, sucrase isomaltase or maltase glucoamylase. The cells express high levels of EGF receptors and of messenger RNA for insulin-like growth factor II.