A human pancreatic tumor cell line has been established from the ascites of a patient with histopathologically confirmed adenocarcinoma of the head of the pancreas and maintained for more than 12 months in the laboratory. Epithelioid tumor cell colonies, which resulted from primary tissue cultures of the ascitic cell component, were mechanically isolated by needle micromanipulation. Tumorigenicity was proven in athymic nude mice. Morphologically the pancreatic tumor epithelial cells grew to confluency with moderately tight adhesion to the culture plastic surface and with free-floating cells in the medium. Upon re-establishment of the tumoral xenograft in tissue culture, the epithelial cells retained their original morphology. Histologically the tumor grown in nude mice exhibited prototypic characteristics of the primary adenocarcinoma in the patient, producing abundant mucin and displaying a broad spectrum of glandular differentiation, which ranged from well to poorly differentiated adenocarcinomas with occasionally localized lymphocytic infiltrations. Furthermore, the tumor expressed carcinoembryonic antigen and human pancreas cancer associated antigen. This tumor line, designated AsPC-1, has been cultured for at least 10 passages in vitro and 3 in vivo. It represents a new model for human pancreatic cancer.