Sublobar resection and the optimum approach for small-sized lung cancer remain controversial. We defined the criteria for the selection of cT1aN0M0 patients for thoracoscopic lung surgery and the criteria for other patients for open lung surgery in 2004. Limited resection for small-sized lung cancer was performed when the diameter of the solid lesion was less than 20% the diameter of lesions of groundglass opacity( GGO). The 5-year overall survival and 5-year disease-free survival( 5Y-DFS) was 89.9% and 91.7%, respectively. The 5Y-DFS according to the pathological stage was as follows:stage IA, 96.5%;IB, 100%;IIA, 50%;IIIA, 66.7%;and stage IV, 100%. According to computed tomography (CT) findings, the 5Y-DFS was as follows:pure GGO lesion, 100%;mixed GGO lesion, 100%;and solid lesion, 84.6%. Lymph node metastases and recurrence were noticed only in patients with a solid lesion. Thus, patients with GGO lesions are considered good candidates for thoracoscopic sublobar resection. In addition, thoracoscopic segmentectomy was performed in cT1bN0M0 patients with GGO lesions, and good prognostic results were obtained;therefore, these patients are also considered good candidates for the procedure.