Tuberculous pleurisy was diagnosed in two patients, a 21-year-old Somali woman and a 19-year-old Surinam man. The first patient suffered from a paradoxical (immunological) reaction and the other had an infectious reaction. Both patients recovered after treatment with tuberculostatic agents and pleural drainage. The pathophysiology of the paradoxical reaction is still largely unclear. Culture continues to be the gold standard in diagnosing tuberculous pleuritis but, in many cases, bacteriological confirmation is not obtained. The (probable) diagnosis is then often made on the basis of a combination of the patient's history, estimation of the risk, physical examination, radiology and histology, and on the basis of a (trial) treatment with tuberculostatic agents. In the diagnostic process, a PCR on the Mycobacterium tuberculosis complex can be helpful. The routine determination of adenosine deaminase and interferon gamma in patients with tuberculous pleurisy is not useful in low-incidence countries such as The Netherlands. The measurement of the in-vitro T-cell reactivity against M. tuberculosis-specific antigens may be of more value in the future. The pharmacotherapy of tuberculous pleurisy is the same as that of pulmonary tuberculosis. Rinsing the pleural cavity is recommended in the case of an infectious reaction. Drainage of pleural fluid is indicated in the case of a paradoxical reaction if there are mechanical difficulties.