Introduction: Paraesophageal hernia (PEH) is a rare condition in children. The symptomatology of these patients is usually non-specific in the form of repeated attacks of respiratory infection and/or recurrent attacks of vomiting but can also lead to serious complications such as intrathoracic gastric strangulation and perforation. Case Report: A 6-year old girl was referred from a regional hospital for haematemesis and abdominal pain. She had fever and sepsis. Physical examination revealed abdominal tenderness, rebound and failure to thrive. Air-fluid level was seen in the posterior of left hemithorax at the AP and lateral chest radiographs. Thorax CT demonstrated pleural fluid, opacity, volume loss and left lung being pushed to the right of heart. Stomach and splenic flexura were moved to the left hemithorax. At laparatomy, stomach and splenic flexura had passed along the esophageal hiatus toward the chest and fundus of the stomach was perforated within the hernia sac. Greater curvature and fundus of the stomach were necrotic and hernia sac and intraabdominal space was filled with food. Stomach was pulled into the abdomen. Hernia sac was excised and defect was primarly repaired. Necrotic areas of the stomach were debrided. Then, perforation of stomach was repaired and gastrostomy was performed. Control esophagogastroduodenography revealed a 2 cm filling defect at the greater curvature and fundus of stomach due to previous gastric resection. Antireflux medical treatment was successful. Conclusion: PEH may be asymptomatic and encountered incidentally. It has the potential for serious complications such as strangulation and perforation which may present with unusual symptoms and physical findings reflecting the original pathology. Due to the risk of these serious complications, elective surgical repair is necessary after diagnosis. © The Journal of Current Pediatrics, published by Galenos Publishing.