A thirty-six year old male patient presented with dyspnea, right-sided chest pain, night sweats and intermittent fever. He has a history of ankylosing spondylitis treated with tumour necrosis factor-alpha (TNF-alpha) antagonist (infliximab). Computed tomography of the chest showed mediastinal lymphadenopathy, right-sided pleural effusion, and atelectasis. The pleural fluid was exudative with lymphocyte dominance. Closed pleural biopsy was nondiagnostic. The adenosine deaminase level of the pleural fluid was 110 U/L. In light of these findings, the patient was diagnosed as tuberculous pleurisy and antituberculous treatment was given. After one month, pleural fluid was markedly reduced.