A high-dose intravenous gamma-globulin (IVGG) therapy was given to two children; one with intractable dermatomyositis (case 1) and the other with polymyositis (case 2). Case 1, a 3-year-6-month-old girl, only poorly responded to the standard oral prednisolone therapy and a pulse therapy with high-dose methyl-prednisolone. This patient showed a complete remission after a course IVGG therapy, 100 mg/kg/day iv. for 5 days, which has been maintained for 6 months up to the present. Case 2, a 13-year-6-month-old girl, also showed little improvement after the oral prednisolone therapy, and transient improvement during plasma exchange therapy. This patient showed fairly good response after three repeated courses of IVGG therapy, but not complete remission.