Spontaneous pneumomediastinum (SPM) is a relatively uncommon, infrequently reported entity. To determine the clinical presentation and sequelae of SPM, data were obtained from 25 patients: 14 from Hadassah University Hospital, and 11 from other medical institutions. The mean age was 18.8 +/- 5.2 years (+/- SD), with a range of 8 to 31 years. The most common presenting complaint was retrosternal pain in 22 patients (88 percent), dyspnea in 15 (60 percent), dysphagia in 10 (40 percent), and weakness in 10 (40 percent). Predisposing factors for the development of SPM could be identified in 18 patients (72 percent). Information on the sequelae of SPM during a mean period of 87.4 +/- 38.0 months following the initial SPM episode was obtained from 23 patients. Recurrent SPM occurred in 1 patient at 18 months, and another patient experienced 4 episodes of recurrent spontaneous pneumothorax. No other long-term sequelae were reported. We conclude that SPM is a benign self-limited disease with diverse clinical manifestations. Although uncommon, recurrences of SPM may be observed.