Seventy-one-year-old woman was visited to our hospital because of dry cough and dyspnea on effort. Fine crackle was audible on both lower lung fields. Joints and skin were normal. Laboratory examination revealed elevation of serum LDH and CRP level. Both anti-nuclear antibody and Jo-1 antibody were negative. Blood gas analysis showed hypoxia after exercise. Chest X-ray film showed reticular shadow in both lower lung fields. Chest CT finding showed patchy area of ground glass attenuation, air-space consolidation, and reticular shadow. Scintigram showed diffuse uptake of Gallium-67 in both lung. Transbronchial biopsy specimen revealed alveolar wall thickness, lymphocyte infiltration and swelling of type II pneumocytes. Bronchoalveolar lavage fluid analysis revealed elevation of CD4/CD8 ratio. She was given a diagnosis of idiopathic interstitial pneumonia. Combination therapy of cyclosporin A and steroid was performed. After therapy, her chest CT findings and her data of pulmonary function test were improved. Then therapy of cyclosporin A was continued and dose of prednisolone was gradually decreased. After that, she was suffered from respiratory tract infection. After administration of antibiotics and cyclosporin A, she was getting well without acute exacerbation of interstitial pneumonia. Since then, she was treated with cyclosporin A only and her pulmonary function test data were gradually improved more. It suggests that cyclosporin A may be useful for the treatment of idiopathic interstitial pneumonia.