A lung hernia, defined as the protrusion of pulmonary tissue and pleural membranes through a defect in the thoracic wall, is a rare event. It can be congenital or acquired, and cervical, thoracic, or diaphragmatic in location. We report the rare occurrence of a congenital atraumatic lung herniation through the azygoesophageal recess. An 8-month-old male infant, who was born at 35 weeks gestation, had a chronic cough. Chest radiography showed haziness at the right lower lobe of the lung (RLL). Chest computed tomography (CT) revealed herniation of the RLL through the azygoesophageal recess. If persistent unilateral haziness is observed on chest radiography, the possibility of lung herniation should be considered.