A colopleural fistula is a rare condition reported to be caused by Crohn’s disease, a malignant tumor of the gastrointestinal tract, and other clinical conditions. Some studies have noted that a sub-diaphragmatic abscess, usually organized following abdominal surgery, may play some role in the formation of this type of fistula. Therefore, a colopleural fistula is a complication very rarely encountered by thoracic surgeons after lung resection.We experienced an extremely rare case of colopleural fistula following a left lower lobectomy for lung aspergillosis. Here, we report a 71-year-old man with a surgical history of proximal gastrectomy for gastric cancer. He underwent left lower lobectomy of the lung for aspergillosis, and a colopleural fistula occurred on the second operative day as a complication. Aspergillus might be responsible for forming a fistula between the colon and lung via the diaphragm, and lung surgery manifested this rare condition. Although some reports suggest that surgical treatment is mandatory to cure this fistula, an immediate colostomy in our case reduced the internal pressure of the colon, thus enabling spontaneous closure of the fistula with appropriate drainage and antibiotics. The patient was discharged in a good condition.