A portosystemic shunt (PSS) is a well-recognized condition causing signs of hepatic disease in young cats. The condition consists of an aberrant vascular communication between the portal and systemic vascular systems. Although medical management can palliate the clinical signs of hepatic disease in these cats, definitive treatment consists of surgical attenuation of the shunting vessel. Surgical treatment is limited in some cats by access to the shunting vessel and in others by creation of portal hypertension if the vessel is completely occluded. The long-term prognosis is good in cats in which the PSS can be completely ligated. Clinical improvement is seen initially in cats in which only partial ligation can be accomplished, but recurrence of clinical signs is common.