Extracorporeal life support (ECLS) is a safe and effective means to keep patients alive during severe respiratory failure that otherwise would be fatal. In addition to direct and indirect treatment of the lungs during ECLS, the technique allows days of time for study and treatment of other conditions and organ failure. The technique has been refined in newborn infants and children, in whom survival rates are high and the technology is proven by prospective randomized trials. ECLS usually is applied to adults with respiratory failure when the mortality risk is over 80%, and, with these indications, the survival rate in experienced centers is 50% to 60%. A new, prospective randomized trial is underway in the United Kingdom. Meanwhile, intensivists who are charged with the management of moribund patients with acute respiratory distress syndrome who fail to respond to other methods of therapy should consider the risks versus benefits of transferring such patients to an ECLS center.