An accurate diagnosis should be made before treatment of autoimmune pancreatitis and immunoglobulin G4-related sclerosing cholangitis. Once a diagnosis has been established, steroids are the standard therapy and symptoms are the major indications. Before steroid therapy, obstructive jaundice and hyperglycemia should be controlled. An initial dose of 0.6 mg/kg/d of oral prednisolone is administered for 2 to 4 weeks, and is gradually tapered over 2 to 3 months. After steroid therapy has begun, blood and imaging tests are performed periodically. Patients with a poor response to steroids should be reevaluated on suspicion of malignancy. To prevent relapse, maintenance therapy using low-dose prednisolone (2.5–5 mg/d) for 1 to 3 years is recommended in Japan. Proximal biliary stricture is reported to be a predictor of relapse. Readministration and dose-up of steroids are effective for relapses. In Western countries, immunosuppressive drugs and rituximab have also been shown to be effective. The optimal treatment regimen should be addressed in future randomized, controlled clinical trials.