A continuous human cell line, COLO 357, with exceptional characteristics was derived from a metastasis of a pancreatic adenocarcinoma. COLO 357 grew as an adhering monolayer with a cell doubling time of 21 h and grew with 10% clonal efficiency in soft agar. COLO 357 cells had numerous lamellar inclusions. The cells elaborated the pancreatic enzymes trypsin, elastase and chymotrypsin. COLO 357 also secreted appreciable amounts of carcinoembryonic antigen and human chorionic gonadotropin. COLO 357 had a chromosome mode of 53 with 20 identifiable Giemsa-banded marker chromosomes. Nine nucleolar organizing regions were found by silver-stained metaphase preparations. COLO 357 has been "fingerprinted" for seven allelic isozymes. This cell line has been maintained in active culture for over 2 years, is preserved in a cell bank, and is available to other investigators.