['Video-assisted thoracoscopic surgery (VATS) segmentectomy for small or early stage non-small cell lung cancer (NSCLC) remains controversial. Here, we investigated the clinical importance of predicting recurrence by Ki-67 in VATS segmentectomy for stage I NSCLC.', 'In a retrospective study, 44 consecutive patients in p-stage I underwent VATS segmentectomy between September 2003 and April 2009. After clinicopathological factors were compared with Ki-67 expression, the relationship between Ki-67 labeling indexes (LI) or mRNA expression by quantitative RT-PCR and prognosis was investigated.', 'Five of 44 VATS segmentectomy patients relapsed. In the relapsed patients, 3 (6.8%) were local recurrences and 2 (4.5%) were distant metastases. There was no significant difference between clinicopathological factors and recurrence; however, patients with Ki-67 LI less than 5% showed better disease-free survival than patients with Ki-67 LI over 5% (p = 0.04). In multivariate Cox regression analysis, although there was no significantly different in disease-free survival by age, histology, tumor size, only Ki-67 LI showed a significant prognostic factor of recurrence (HR = 12.5, 95% CI = [1.1-1407], p = 0.04).'] Is ki-67 labeling index associated with recurrence after segmentectomy under video-assisted thoracoscopic surgery in stage I non-small cell lung cancer?