Two human pancreatic carcinoma cell lines, PC-1 and PC-2, were established from nude mice xenografts derived from metastatic pancreatic carcinomas of two patients. The two cell lines propagated continuously in vitro over 19 and 19.5 months. The cells grow in a monolayered sheet with doubling times of 47 hours for PC-1 and 58 hours for PC-2. The cells exhibited epithelial morphology and were confirmed to be malignant epithelial cell lines by morphological study, CEA and cytokeratin immunocytochemistry, flow cytometry and Con A test. The tumors caused by inoculation of cultured PC-1 and PC-2 into nude mice retained the histological and ultrastructural features of the original tumors. The findings proved that the two cell lines were human exocrine pancreatic adenocarcinoma cell lines. Chromosomal analysis together with flow cytometry data revealed that the two cell lines had the human aneuploid karyotypic features with model chromosome numbers of 48 and 66.