Tumor necrosis factor-alpha (TNF-α) plays a important role in the pathogenesis of rheumatoid arthritis and Crohn's disease, TNF-α antagonist has been widely used for these disease, but it also plays a major role in cell mediated immunity. Cryptococcus neoformans, an encapsulated, ubiquitous environmental yeast, is pathogenic for humans, primarily those with compromised immune function. Cryptococcus neoformans is believed to be a facultative intracellular pathogen. We report a case of pulmonary cryptococcosis after chimeric anti-TNF monoclonal antibody therapy. No case has been reported in Korea for the best of our knowledge. A 66-year old woman was admitted because of severe cough. She was diagnosed to have rheumatoid arthritis 4 years ago and taken prednisolone and methotrexate. She was started on infliximab and received ten doses, the last dose being administered 6 weeks prior to above symptom. Chest PA and computed tomography of chest revealed multifocal consolidative lesions in both lungs. Pulmonary cryptococcosis confirmed by thoracoscopic lung biopsy tissue stained with Grocott-Gomori methenamine-silver (GMS). Initially the lung lesion responded to amphotericin B but leukopenia developed after 12 days of treatment. It was changed to fluconazole, then leukopenia and the pneumonia also improved. Physicians should remind pulmonary cryptococcosis in patients receiving TNF-α antagonist therapy.