Autoimmune hepatitis (AIH) is a disorder of unknown etiology, which often progresses to cirrhosis and carries a high mortality, even though its treatment with corticosteroids has become common. Hepatocellular carcinoma (HCC) has been reported as a rare complication of AIH. We describe herein a patient with HCC associated with AIH, in whom microwave coagulation therapy provided a means of definitive management, and we also review the literature. Male sex and longstanding cirrhosis seem to be the risk factors for hepatocarcinogenesis in AIH. The prognosis of this disease is extremely poor because of the low resectability caused by poor hepatic reserve. It is important to pay attention to hepatic disorders and the possible development of HCC at the time of diagnosis of AIH. Surgeons should select suitable treatment, without undue surgical stress, whenever the diagnosis of HCC has been established. Microwave coagulation therapy is a preferred option for the treatment of high-risk patients with poor hepatic reserve or unresectable multiple HCCs.