Two human pancreatic carcinoma cell lines, designated HuP-T3 and HuP-T4, were established from the ascites of pancreatic cancer patients with carcinomatous peritonitis. The cell lines were grown in monolayer cultures and had population doubling times of 38.6 and 37.1 h, respectively. HuP-T4 secreted large amounts of CEA and CA19-9 into the medium, and HuP-T3 produced a small amount of CEA, but no CA19-9. Both cell lines showed tumorigenicity in nude mice. Histologically, the HuP-T3-derived tumor was poorly differentiated adenocarcinoma, and the HuP-T4-derived tumor was well differentiated papillotubular adenocarcinoma. In lectin histochemistry at both light and electron microscopic levels, the most striking difference between the lectin binding properties of the two cell lines and those of control normal pancreatic ductal cells was that soybean agglutinin (SBA) bound to both cell lines, but not to controls. These newly established cell lines should be useful models that will contribute to clarifying the biological and biochemical characteristics of pancreatic cancer.