We have examined the lungs from five patients who died with the adult respiratory distress syndrome (ARDS). Pressure volume curves were obtained and bronchoalveolar lavage fluid was studied on a surface balance. The pressure volume curves revealed reduced compliance compared to normal or near normal lungs. A significant loss of volume was also found. The data obtained from the surface balance studies show a normal range of minimum surface tension when compared to "normals," but the ARDS lung lavage fluid revealed an increase in surface film compressibility relative to "normal." The increased compressibility may be an important factor contributing to the stiff lungs of patients with the adult respiratory distress syndrome.