Fifteen patients (range of ages, 18 to 35 years) who survived an acute episode of the adult respiratory distress syndrome caused by mechanical or thermal injuries, sepsis, and shock were studied during 1 to 30 months after recovery. The patients had had no previous pulmonary diseases, and only two had been smokers. All of the patients were asymptomatic, and their chest x-ray films were normal on follow-up examination. Tests of pulmonary function revealed mild abnormalities which consisted of reduction of pulmonary volumes, decreased carbon monoxide diffusing capacity, and a mild increase of alveolar-arterial oxygen pressure gradients in the early stage after recovery. Improvement was noted after a few months, but eight patients still had mild reduction of pulmonary volume after one to two years. No correlation could be established between the severity of the adult respiratory distress syndrome, therapy with mechanically assisted ventilation, the duration of exposure to supplemental oxygen, the fractional concentration of oxygen in the inspired gas, and the degree of residual functional defect.