Objective: The following case report elicits the treatment of a 55-year-old male who was diagnosed with a surinfected mediastinal chyloma as a complication of mediastinoscopy and radiotherapy for a primary adenocarcinoma of the right lung (cT2aN2M0). Methods: The patient was admitted to the hospital after radiographical imaging showed a surinfected mediastinal chyloma. CT-guided percutaneous drainage was performed and via gastroscopy a fistula was diagnosed for which a full covered stent was placed. Then, a right thoracotomy was performed to wash out the chylous cavity, to seal the thoracic duct and to cover the other end of the fistula with an intercostal muscle flap. Results: Postoperative imaging showed a clear reduction of the mediastinal mass with no residual air-fluid level. Realimention was possible three days after placement of the stent. The patient was discharged after 11 days. There was no recurrence of the chyloma. Fistulisation did recur after removal of the stent. Conclusion: Surinfected mediastinal chyloma due to oesopagho-mediastinal fistula is an extremely rare complication after cervical mediastinoscopy and radiotherapy. Open drainage of the chyloma and total coverage of the fistula can control infection and prevent recurrence on short term.