Pneumomediastinum is a rare entity that is defined as free air in the mediastinal space. A 26-year-old male patient was admitted with pneumomediastinum as an unexpected complication of robotic surgery. Diffuse subcutanous emphysema was observed suddenly on Postoperative Day 3 without respiratory distress. Air trapping into the mediastinum was seen on chest X-ray and computed tomography. The patient was followed in the intensive care unit for 7 days and managed conservatively. Subcutaneous emphysema reduced gradually. In conclusion, although it is a rare condition, pneumomediastinum should be kept in mind as a complication of robotic cardiac surgery.