We report a case of corticosteroid-resistant nonspecific interstitial pneumonia associated with dermatomyositis. The patient was successfully treated with a combination of cyclosporin A (CsA) and prednisolone. A 28-year-old man was admitted complaining of skin eruptions, myalgia, and weakness, and dyspnea on exertion. Characteristic skin lesions such as erythema around the nails, teleangiectasis, and edema of the eyelids were observed. Dermatomyositis was diagnosed based on the diagnostic criteria, including the skin biopsy findings. Laboratory examination showed elevation of creatine kinase, but the anti-Jo-1 antibody was negative. Chest X-ray on admission showed reticular shadows and airspace consolidation mainly in both lower lung fields. Lung biopsy specimens taken under video-assisted thoracoscopic surgery revealed infiltration of lymphocytes into the thickened alveolar septa, and this revelation was compatible with the description of cellular nonspecific interstitial pneumonia. Administration of corticosteroids with steroid pulse therapy resulted in with improvement of interstitial pneumonia. However, after the combination therapy of corticosteroid with daily oral administration of 100-150 mg of CsA had been initiated, hypoxemia recovered swiftly in 5 days, and respiratory symptoms improved gradually, but steadily. Oral administration of corticosteroid and CsA was eventually tapered off and terminated completely 5 years later. The patient has been quite well with no treatment for two and a half years. The case presented here implies that CsA combined with corticosteroid may be efficacious in the treatment of interstitial pneumonia associated with dermatomyositis which is refractory to corticosteroid therapy.