The prevalence of nonspecific interstitial pneumonitis(NSIP) in HIV-positive patients with pulmonary disease has varied from 11 to 38%. But NSIP in HIV-positive patients is indistinguishable from Pneu mocystis carinii pneumonia(PCP) clinically and radiologically. The number of HIV-positive patients is less in Korea than in western developed countries, so little attention has been paid to the differential diagnosis between NSIP and PCP. We report a case of NSIP in HIV-positive, 61-year-old man which mimicked PCP. He presented with cough, sputum and mild exertional dyspnea. Lung sound was clear. But, chest X-ray and HRCT demonstrated diffuse patch and bilateral ground-glass opacities in central and perihilar area of both lung. Microbial pathogens were not found on sputum, BAL flued and tissues taken by TBLB. In transbronchial lung biopsy specimen, interstitial infiltrates with lymphocytes were distributed on peribronchiolar regions. A pathlolgic diagnosis of NSIP was suggested, he received symptomatic treatment. The follow-up chest X-ray showed near complete resolution.