A study was carried out on 167 patients with tuberculous pleural effusion. It was found that tuberculosis is the commonest cause of pleural effusion in Nigerians, forming 56% of the 300 cases which were reviewed. The clinical and radiological features are described and the characteristics of the fluid are discussed. The pleural fluid was predominantly lymphocytic in 83% of cases, the glucose concentration was less than 50 mg/100 ml in 54%, and M. tuberculosis was cultured from only 12%. Pleural biopsy was found useful in the diagnosis in 53% of cases. The management and prognosis of tuberculous effusions are briefly discussed. Six of the 167 patients died despite chemotherapy, but all of them were moribund at the time of admission to hospital.