Idiopathic interstitial pneumonia is a group of lung disease classified by clinical, radiological and pathologic findings. Steroid is described in many reports as an effective treatment for the idiopathic interstitial pneumonitis. For the treatment of steroid non-responders, immuno-suppressive or cytotoxic agents are used as second line drug of choice. We experienced a case of nonspecific interstitial pneumonitis who was treated initially with glucocorticoid and antibiotics without effects, but later did respond to cyclosporin treatment. This 63 year-old patient was admitted due to dyspnea, cough, and sputum production. He was started on glucocorticoid and antibiotics after he was diagnosed as having nonspecific interstitial pneumonitis by open lung biopsy. The initial steroid treatment was not effective, however, after cyclosprin treatment, the patient showed clinical and radiologic improvements.