In three cases of pulmonary tuberculosis associated with the adult respiratory distress syndrome the clinical features, which were similar to those of patients with miliary tuberculosis and adult respiratory distress syndrome, included a history of cough, fever, and dyspnoea on effort, and the physical signs of fever, tachypnoea, pulmonary adventitious sounds, tachycardia, and hepatomegaly. In these cases the radiological features, though suggestive of diffuse pulmonary oedema, were more prominent on the side in which the cavitatory lesion appeared. The diagnosis of tuberculosis was made easily from direct examination of sputum. Despite early ventilatory support and antituberculous therapy, two of the three patients died. Postmortem examination of the lungs in these cases showed evidence of acute alveolar damage (loss of type 1 pneumocytes and the presence of hyaline membranes within alveolar ducts) and of chronic alveolar damage (interstitial and alveolar fibrosis).