A retrospective cohort study involving 29 Japanese patients with autoimmune hepatitis (AIH) was performed to clarify factors that predict the efficacy of prednisolone and the occurrence of various serious adverse effects. Independent predictors were identified by logistic analysis and with use of the Cox proportional hazard model. Responses to prednisolone were noted in 28 patients, who were classified into the complete remission group (52%) or the relapse group (48%). Multivariate analysis identified alanine aminotransferase, alkaline phosphatase, and immoglobulin G levels as independent predictors of relapse. The adverse effects most frequently observed were diabetes mellitus (37.9%), psychiatric/ neurologic symptoms (34.5%), and circulatory symptoms (34.5%). Predictive factors included lactate dehydrogenase, albumin, and fasting blood glucose levels for diabetes mellitus, alkaline phosphatase and C-reactive protein for psychiatric/ neurologic symptoms, and autoimmune hepatitis score and lactate dehydrogenase for circulatory symptoms. Selection of an optimal treatment method for individual patients may be possible after the risks of relapse and adverse effects have been estimated.