Background. It is difficult to distinguish the development of granuloma along the staple line after segmentectomy from tumor recurrence. Case. A 70-year-old male underwent left S⁸ segmentectomy with lymph node dissection for early stage IA lung adenocarcinoma using video-assisted thoracic surgery. One year later, a routine chest CT scan disclosed a mass adjacent to the previous segmentectomy site. Although local recurrence of lung cancer was suspected, a bronchoscopic examination showed no recurrence, and the results of a bacteriological examination were nonspecific. Steroid therapy was therefore initiated based on our concern for the potential of organizing pneumonia. The mass lesion subsequently shrank in size, almost disappearing. Interval chest CT, however, demonstrated regrowth of the site of consolidation along the staple line. The steroid therapy was repeated; however, the area of consolidation continued to grow. Completion left lower lobectomy was thus performed, as the possibility of local cancer recurrence could not be excluded. At the time of thoracotomy, a hard white mass was palpated along the staple line in the left lower lobe. A pathological analysis revealed epithelioid granuloma with caseating necrosis, and Mycobacterium avium complex (MAC) grew from a culture of the specimen. Therefore, the lesion was thought to be a granuloma caused by MAC infection at the previous segmentectomy staple line. Conclusions. We herein report a rare case of pulmonary granuloma associated with non-tuberculous mycobacteriosis occurring at the staple line after segmentectomy for lung cancer. In addition to local recurrence or secondary primary lung cancer, the possibility of mycobacterial granuloma should be considered in cases in which pulmonary nodules are detected on the staple line after pulmonary resection.