BACKGROUND Although lobectomy is the standard surgical procedure for non-small cell lung cancer (NSCLC), recent studies show favorable outcomes after limited resection in patients with small-sized peripheral tumors. We conducted a randomized controlled trial of such patients to estimate postoperative outcomes and pulmonary function following these surgical techniques. METHODS Between 2005 and 2008, eligible patients with tumors of 2 cm or less were randomly assigned 1:1 to undergo lobectomy or limited resection; 32 and 33 NSCLC patients in each group, respectively, were analyzed. The primary end points were 5-year overall survival (OS) and disease-free survival (DFS), while the secondary end points were postoperative pulmonary function including forced vital capacity (FVC) and forced expiratory volume in 1 second (FEV1). RESULTS The 5-year OS rates were 93.8% and 90.9% in the lobectomy and limited resection groups, respectively (P=0.921). The 5-year DFS rates were 93.8% and 90.9% in the lobectomy and limited resection groups, respectively (P=0.714). These rates did not differ significantly between the two resection groups. The median postoperative/preoperative FVC ratios were 84.1% and 90.0% in the lobectomy and limited resection groups, respectively, while the median postoperative/preoperative FEV1 ratios were 81.9% and 89.1%, respectively. Both ratios were significantly higher in the limited resection group (P=0.032 and P=0.005 for FVC and FEV1 ratios, respectively). CONCLUSIONS A similar outcome, with more preserved postoperative pulmonary function, was observed in patients who underwent limited resection compared to those who underwent lobectomy. Ongoing large-scale multi-institutional prospective randomized trials of lobar versus sublobar resection in patients with small peripheral NSCLCs will hopefully provide definitive information about intentional limited resection of small peripheral tumors.