Pulmonary edema occurring in divers using a self-contained underwater breathing apparatus (scuba) is an uncommon, probably under-reported, but potentially life-threatening and recurrent condition. We report six episodes of pulmonary edema in five scuba divers seen during a period of 15 months. The four men and one woman ranged in age from 37 to 56 years and two were treated for hypertension. Symptoms were mostly dyspnea onset at depth, cough, hemoptysis and hypoxemia, which in the recurrent case led to cardiac arrest and death. All cases occurred in rather cold water. Findings on thoracic computed tomography (CT) scanning ranged from pleural effusion to ground-glass opacities restricted to a few areas of the lung. The complex underlying mechanisms that would contribute to a raised transalveolar pressure or to a disruption of the blood-gas barrier are discussed. It is important for emergency care providers to be aware of this syndrome for prompt recognition and optimal treatment.