Nuss procedure has become the treatment of choice in pectus excavatum mainly because of the excellent functional and cosmetic results. Despite the good results, several complications have been reported. The aim of this study is to describe a case of thoracic outlet syndrome (TOS) after Nuss procedure and review the management of such rare complication. A 15-year-old boy otherwise healthy was submitted to Nuss procedure, with no perioperative complications. Two-weeks later, the patient complained of right-hand paresthesia, progressive weakness of the right arm and coldness. After imaging and electromyography, TOS diagnosis was established. Removal of the bar was proposed but refused by the patient. Conservative management with rehabilitation exercising and nerve nourishing was initiated. At 7 months, the patient recovered arm and hand function. Abrupt structural changes of thoracic cavity with marked elevation of the upper chest induce nerve and vascular compression arousing a TOS and should be acknowledged as one potential complication of Nuss procedure. Conservative management can be an alternative treatment to bar removal, showing good results on functional recovery in early stages of compression.