Objective: To establish an appropriate steroid treatment regimen for autoimmune pancreatitis (AIP). Methods: A retrospective survey of AIP treatment was conducted in 17 centres in Japan. The main outcome measures were rate of remission and relapse. Results: Of 563 patients with AIP, 459 (82%) received steroid treatment. The remission rate of steroid-treated AIP was 98%, which was significantly higher than that of patients without steroid treatment (74%, 77/104; pConclusions: The major indication for steroid treatment in AIP is the presence of symptoms. An initial prednisolone dose of 0.6 mg/kg/day, is recommend, which is then reduced to a maintenance dose over a period of 3–6 months. Maintenance treatment with low-dose steroid reduces but dose not eliminate relapses.