Patients with shock lung syndrome were identified as those who developed acute respiratory failure after a profound episode of hypotension secondary to hemorrhagic, gram-negative, or endotoxic shock. In this study, each of the 10 patients with shock lung syndrome received methylprednisolone sodium succinate, 30 mg. per kilogram, intravenously every 6 hours for 48 hours. In addition, all patients were supported with mechanical ventilation, with or without positive end-expiratory pressure (PEEP). Arterial oxygenation improved markedly, and pulmonary edema resolved in all patients. Nine were discharged from the hospital and one died subsequently of disseminated intravascular coagulation. This study demonstrated a significant improvement in mortality rate with repeated pharmacologic doses of methylprednisolone compared to previously reported mortality rates of 60 to 90 per cent in patients with shock lung syndrome treated without repeated pharmacologic doses of steroid therapy.