In pulmonary hernia or pneumocele the lung protrudes through a defect in the chest wall. In this report of a case of spontaneous intercostal lung hernia, we describe the pathogenesis and classification of such hernias, including signs, symptoms, radiological findings and treatment methods. Our patient presented with severe chest pain at the base of the left hemithorax. A chest film and computed tomography of the region showed an left intercostal hernia. Surgical treatment was successful.