Spontaneous pneumomediastinum (SPM) is defined as the presence of air in the mediastinum, developing in the absence of traumatic, iatrogenic, or preceding pulmonary pathologies (emphysema, chronic bronchitis, and lung cancer). The aim of this study was to review our experiences with SPM, underlining its symptomatology, diagnosis, treatment, and followup, and defining a reasonable course of assessment and management. A retrospective case series was conducted to identify adult patients with SPM who were diagnosed and treated in our institution between 1998 and 2005. Eighteen patients (10 males) were identified (average age = 25 +/- 4.8 years). Acute onset of chest pain was the predominant symptom at presentation. All patients developed clinically evident subcutaneous emphysema and underwent chest computerized tomography. Fiber bronchoscopy and echocardiogram were used selectively (8 patients). The average hospital stay was 6 (+/-1.4) days. Sixteen patients were conservatively treated, and only two patients were treated with thoracic drainage due to a related pneumothorax. The disease followed a benign evolution in all patients and, as of today, no relapse has been reported. SPM is an uncommon pathology with a usually benign course. The authors discuss SPM. A diagnostic algorithmic approach is necessary to rule out severe secondary entities and consequences that need urgent treatment.