A retrospective study of 83 cases of tuberculous pleural effusion showed that the mean age of the patients was 44 years and 10 patients (12%) were over the age of 70. Pleural fluid was smear positive for tubercle bacilli in none but culture positive in 23% of the cases. Pleural biopsy was a more sensitive method of diagnosis with granulomatous inflammation seen in 97% of cases. Five patients developed significant pleural thickening during chemotherapy requiring decortication. Twenty-two patients with tuberculous effusion diagnosed and treated over 2 years previously were traced for reassessment. None of them had significant pleural thickening and lung function tests did not show significant impairment compared to matched control subjects.