ABSTRACT: Importance:Laparoscopic distal gastrectomy is accepted as a more effective approach to conventional open distal gastrectomy for early-stage gastric cancer. However, efficacy for locally advanced gastric cancer remains uncertain. Objective:To compare 3-year disease-free survival for patients with locally advanced gastric cancer after laparoscopic distal gastrectomy or open distal gastrectomy. Design, Setting, and Patients:The study was a noninferiority, open-label, randomized clinical trial at 14 centers in China. A total of 1056 eligible patients with clinical stage T2, T3, or T4a gastric cancer without bulky nodes or distant metastases were enrolled from September 2012 to December 2014. Final follow-up was on December 31, 2017. Interventions:Participants were randomized in a 1:1 ratio after stratification by site, age, cancer stage, and histology to undergo either laparoscopic distal gastrectomy (n?=?528) or open distal gastrectomy (n?=?528) with D2 lymphadenectomy. Main Outcomes and Measures:The primary end point was 3-year disease-free survival with a noninferiority margin of -10% to compare laparoscopic distal gastrectomy with open distal gastrectomy. Secondary end points of 3-year overall survival and recurrence patterns were tested for superiority. Results:Among 1056 patients, 1039 (98.4%; mean age, 56.2 years; 313 [30.1%] women) had surgery (laparoscopic distal gastrectomy [n=519] vs open distal gastrectomy [n=520]), and 999 (94.6%) completed the study. Three-year disease-free survival rate was 76.5% in the laparoscopic distal gastrectomy group and 77.8% in the open distal gastrectomy group, absolute difference of -1.3% and a 1-sided 97.5% CI of -6.5% to ?, not crossing the prespecified noninferiority margin. Three-year overall survival rate (laparoscopic distal gastrectomy vs open distal gastrectomy: 83.1% vs 85.2%; adjusted hazard ratio, 1.19; 95% CI, 0.87 to 1.64; P?=?.28) and cumulative incidence of recurrence over the 3-year period (laparoscopic distal gastrectomy vs open distal gastrectomy: 18.8% vs 16.5%; subhazard ratio, 1.15; 95% CI, 0.86 to 1.54; P?=?.35) did not significantly differ between laparoscopic distal gastrectomy and open distal gastrectomy groups. Conclusions and Relevance:Among patients with a preoperative clinical stage indicating locally advanced gastric cancer, laparoscopic distal gastrectomy, compared with open distal gastrectomy, did not result in inferior disease-free survival at 3 years. Trial Registration:ClinicalTrials.gov Identifier: NCT01609309.