While the use of segmentectomy to treat lung cancer remains controversial, it has recently gained status as a radical surgery for cT1aN0M0 non-small cell lung cancer. I herein review the literature regarding segmentectomy and present my data to discuss the following issues: the prognosis after segmentectomy; local recurrence; the area required for lymph node dissection at the hilum and mediastinum; the technique used to cut the intersegmental plane; the selection of the lymph nodes for frozen sections; the postoperative pulmonary function; the role of completion lobectomy after radical segmentectomy for cT1N0M0/pN1-2; expectations and concerns regarding the randomized controlled trial JCOG0802; and the future of segmentectomy.