More than five years of clinical and animal experience with the use of a transjugular approach to the liver, biliary system, and portal circulation is reviewed. It has been of clinical value in connection with hepatic manometry and venography, liver biopsy, and cholangiography. Satisfactory hepatic manometry and venography were achieved by the transjugular approach in all 47 cases where attempted; diagnostic liver specimens were obtained in 71 of 83 patients (86 percent); and cholangiography was successful in 48 of 52 patients with enlarged intrahepatic ducts (92 percent). No complications occurred with these studies. In animals, transjugular catheterization was used as a means for portal, mesenteric, and pancreatic venography. These procedures are ready for diagnostic clinical use. Therapeutic techniques explored in animals include intravascular tamponade of gastric coronary vein and the nonsurgical creation of intrahepatic portacaval shunts, both of promise in the future management of massive gastrointestinal bleeding from varices.