Transumbilical and percutaneous transhepatic catheterization is performed of pancreatic veins. The normal phlebographic anatomy is reported together with the findings in patients with carcinoma of the pancreas. Selective catheterization of pancreatic veins with hormone essay for tumor localization is performed in two patients with islet cell tumor of the pancreas. The authors suggest this to be a valuable method in the diagnosis of endocrine tumors of the pancreas.