Intercostal hernia can occur after blunt trauma and can also complicate thoracotomy. This report describes a 13-year-old liver transplant recipient with chronic asymptomatic intercostal hernia at site of thoracotomy. This hernia became manifest upon development of spontaneous pneumothorax. She presented with pleuritic pain and radiographic evidence of spontaneous pneumothorax. Her history included liver transplantation at age 19 months for tyrosinemia, posttransplant lymphoproliferative disorder at age 7 years with thoracotomy for lung biopsy, and prolonged corticosteroid administration. Examination and computed tomography revealed an intercostal hernia. She underwent repair of hernia, stapled resection of apical blebs, and pleurodesis. Reconstruction of chest wall involved rib fracture and intercostal approximation with nonabsorbable sutures covered by serratus muscle advancement. She is symptom free with intact repair 2 years and 9 months after surgery and is able to participate in vigorous physical activity. This is the first report of an intercostal hernia detected upon development of spontaneous pneumothorax. The hernia occurred at the site of a prior thoracotomy, possibly because of impaired healing from corticosteroid administration. This case suggests that nonabsorbable sutures should be used for intercostal approximation after thoracotomy in patients with impaired wound healing.