The adult respiratory distress syndrome (ARDS) is a syndrome of diffuse lung injury with a high mortality rate. We evaluated retrospectively 35 adult patients with ARDS. Their overall mortality rate was 69% and was related to their age (32 ± 14 yr in survivors and 54 ± 15 yr in nonsurvivors; p < .001) and to the number of complications during their illness (1.4 complications in survivors, 2.6 in nonsurvivors; p < .005). The ARDS patients, due to an infectious etiology, incurred a 75% mortality rate, while those with a noninfectious etiology of ARDS had a 55% mortality rate (nonsignificant). Neither a simplified acute physiology score nor a respiratory failure severity index was significantly different between survivors and nonsurvivors on admission. The mean PEEP level on admission in survivors was 8.1 ± 4.6 cm H2O and in nonsurvivors 3.7 ± 3.9 cm H2O (p < .025). We conclude that the age of the patients and superimposed multiple system organ failure are probably related with the still high mortality rate of this syndrome.