We succeeded in an establishment of a human pancreatic cancer cell line (PK-1) from liver metastasis of pancreatic cancer. Primary pancreatic cancer cells grew as islands surrounded by fibroblastic cells. However, these fibroblastic cells were gradually omitted by the polygonal shaped cancer cells. This cell line contained neither zymogen granules nor trypsin indicating that this pancreatic cancer originated from pancreatic duct cells. Modal chromosome numbers of this cell line were 42 and 72 and the doubling time was 48 hr. This cell line was transplantable in athymic nude mice to form progressive tumors which had histology similar to that of the original cancer (papillotubular adenocarcinoma). Neither AFP nor ferritin but CEA was detected on the surface and in the cytoplasm of this cell line in indirect immunofluorescence. Rabbit antiserum against this pancreatic cancer cell line detected pancreatic cancer associated antigen besides CEA in the culture supernatant. This antiserum reacted with sera from patients with pancreatic cancer to form a distinct precipitin line in agarose gel which fused with the precipitin line formed between the culture supernatant of this cell line and the antiserum.