Using adult guinea-pigs, we have developed an experimental model in which alveolar surfactant phospholipids are removed by repeated lung lavage in vivo, and in which the short-term survival of the animals is ensured by artificial ventilation. Blood gases, parameters of lung mechanics, and histologic and electron microscopic findings indicate that the lavage procedure induces a condition similar to the adult respiratory distress syndrome. We propose that our technique might be used for evaluation of pharmacological agents and various forms of artificial ventilation which have been suggested for treatment of this disease.