An 8 years and 5 months old Miniature Dachshund, who showed weight loss for 7 months, was diagnosed as having a hepatic arteriovenous fistula (HAVF) with acquired portal circulation shunt (APSS). Hepatic lobectomy of the outer left lobe including the HAVF and closure of a part of the APSS were performed. Postoperatively, mild decline in liver function and hyperammonemia persisted for some time , but liver enzyme values and blood ammonia levels nearly normalized 6 months after the operation.