A lobectomy is the standard surgical procedure for non-small cell lung cancer (NSCLC), though recently a limited resection is more likely chosen for small-sized early stage disease. To elucidate the effectiveness of an intentional segmentectomy as a curative procedure, factors associated with survival after the procedure were examined in a long-term retrospective study carried out at a single institute. Patients with stage I, II, or III disease NSCLC who underwent a segmentectomy between 1980 and 2002 (n = 144) were retrospectively studied and the results compared with those who underwent a lobectomy during the same period (n = 1241). Tumor size, nodal involvement, pleural involvement, and histological type were independent significant prognostic factors in patients who received a segmentectomy. Six patients had a large cell carcinoma and each died from the disease within 5 years after the segmentectomy. In patients with p-T1N0M0 (stage IA) disease and a tumor smaller than 2 cm, except for large cell carcinomas, the 5- and 10-year survival rates were 83% and 83%, respectively, after a segmentectomy, and 81% and 64%, respectively, after a lobectomy (p = 0.66). In patients with p-T1N0M0 disease and a tumor diameter exceeding 2 cm, the 5- and 10-year survival rates were 58% and 58%, respectively, after a segmentectomy, and 78% and 60%, respectively, after a lobectomy (p = 0.057). We concluded that histological type and tumor size were relevant for determining the indication of an intentional segmentectomy for NSCLC with stage IA disease.