To evaluate the relationship between esophageal varices and the azygos vein--which is generally considered to drain the major part of the esophageal variceal blood--we examined 36 patients with portal hypertension using percutaneous transhepatic cine-portography. The patients were classified into three groups (azygos, cervical and combined) according to the amount of blood to be considered drained by the azygos vein. Eighteen patients (50%) fell into the azygos type group, five (14%) into the cervical, and 13 (36%) into the combined. Highly developed esophageal varices were recognized endoscopically in all patients in the combined and cervical type groups while some of the patients in the azygos type group had less well developed varices. In the azygos type group, there was a tendency for the varices to be increasingly severe the higher the part of the azygos vein they drained into. Because it helps us to fully comprehend the significance of the azygos venous blood flow and the occasionally uncertain effect of endoscopic injection sclerotherapy for esophageal varices, it is important to evaluate the drainage route of esophageal varices in vivo and in detail. Percutaneous transhepatic cine-portography is the useful method for this purpose as it enables us to visualize even the most minute blood stream.