Esophageal hiatal hernia is the hernia of a part of or the whole of stomach to posterior mediastinum through esophageal hiatus. Esophageal hiatal hernia can be classified as sliding hiatal hernia (type I), paraesophageal (type II), combined sliding and paraesophageal (type III), and complex paraesophageal (type IV). Type III and IV are clinically classified as paraesophageal hernia. The authors by chance found cystic mass filled with air in the lower lobe of the right lung during the treatment of mycoplasma pneumonia of 10 month-old patient. It was found to be paraesophageal hernia on the chest computed tomography and treated with the operation. As complex paraesophageal hernia is not usual among infants, the authors report it here with literature review.