Background: Although radical gastrectomy with D2 lymph node dissection has become the standard surgical approach for locally advanced gastric cancer, patients still have a poor prognosis after operation. Previously, we proposed laparoscopic distal gastrectomy (D2 lymphadenectomy plus complete mesogastrium excision [D2 + CME]) as an optimized surgical procedure for locally advanced gastric cancer. By dissection along the boundary of the mesogastrium, D2 + CME resected proximal segments of the dorsal mesogastrium completely with less blood loss, and it improved the short-term surgical outcome. However, the oncologic therapeutic effect of D2 + CME has not yet been confirmed. Methods/design: A single-center, prospective, parallel-group, randomized controlled trial of laparoscopic distal gastrectomy with D2 + CME versus conventional D2 was conducted for patients with locally advanced gastric cancer at Tongji Hospital, Wuhan, China. In total, 336 patients who met the following eligibly criteria were included and were randomized to receive either the D2 + CME or D2 procedure: (1) pathologically proven adenocarcinoma; (2) 18 to 75 years old; cT2-4, N0-3, M0 at preoperative evaluation; (3) expected curative resection via laparoscopic distal gastrectomy; (4) no history of other cancer, chemotherapy, or radiotherapy; (5) no history of upper abdominal operation; and (6) perioperative American Society of Anesthesiologists class I, II, or III. The primary endpoint is 3 years of disease-free survival. The secondary endpoints are overall survival, recurrence pattern, mortality, morbidity, postoperative recovery course, and other parameters. Discussion: Previous studies have demonstrated the safety and feasibility of D2 + CME for locally advanced gastric cancer; however, there is still a lack of evidence to support its therapeutic effect. Thus, we performed this randomized trial to investigate whether D2 + CME can improve oncologic outcomes of patients with locally advanced gastric cancer. The findings from this trial may potentially optimize the surgical procedure and may improve the prognosis of patients with locally advanced gastric cancer.