Abstract A 36-year-old male patient with dermatomyo-sitis (DM) associated with rapidly progressive interstitial pneumonia (IP) was successfully treated by high-dose intravenous immunoglobulin (IVIG). He suffered from myopathy, skin lesions, and IP. In spite of the treatment with a high-dose corticosteroid, IP progressed rapidly. Then high-dose intravenous immunoglobulin (20 g/day, 4 days) was administered. The skin lesions, myopathy, and pulmonary lesions improved. High-dose IVIG was considered to be a relatively safe and effective treatment for progressive IP associated with DM.