Retroperitoneal fibrosis (RF) is a disorder characterized by the presence of a retroperitoneal mass and concurrent systemic inflammation. Some cases of RF are recognized as belonging to the spectrum of immunoglobulin G4-related disease (IgG4-RD). Glucocorticoids are highly effective for treatment of retroperitoneal fibrosis, although the optimal dose and duration of therapy have not been established. An initial dose of prednisone (40-60 mg) daily is usually administered with a tapering scheme. We report on a 55-year-old man diagnosed with IgG4-related RF and successfully treated with a 3-day course of daily 250 mg (4 mg/kg) intravenous methylprednisolone, which resulted in the prompt resolution of urinary obstruction and systemic symptoms.