Background: We previously reported that the superiority of bursectomy was not demonstrated for subserosal(SS)/serosal(SE) gastric cancer by the second interim analysis performed with 54% of the expected events observed. We report the final 5-year follow-up data. Methods: Eligibility criteria included histologically proven adenocarcinoma of the stomach, cT3(SS) or cT4a(SE). Patients were intraoperatively randomized to non-bursectomy arm or bursectomy arm. Primary endpoint was overall survival (OS), and secondary endpoint was relapse-free survival (RFS). A total of 1,200 patients were required to detect a hazard ratio of 0.77 with a one-sided alpha of 5% and 80% power. Results: A total of 1204 eligible patients with cT3 / cT4a gastric cancer were randomized (602 in non-bursectomy arm, 602 in bursectomy arm, respectively). Patients’ background and operative procedures were well balanced between the arms. The 5y-OS were 76.5% (95% CI, 72.8 to 79.7) in non-bursectomy arm and 74.9% (71.2 to 78.2) in bursectomy arm. Hazard ratio (HR) for bursectomy was 1.03 (0.83-1.27, one-sided p = 0.598). The 5y-RFS were 70.7% (66.9 to 74.2) in non-bursectomy arm and 66.8% (62.9 to 70.5) in bursectomy arm [HR: 1.131 (0.93-1.38)]. HR for death was almost similar in all sub-categories (0.73-1.29) except cN2 (13th edition of Japanese Classification of Gastric Carcinoma); HR classified by cN was 1.06 (95% CI: 0.75-1.49) for cN0 (n = 521), 1.25 (0.92-1.71) for cN1 (n = 525), and 0.59 (0.32-1.06) for cN2 (n = 158) (p = 0.048 for interaction). The most frequent site of recurrence was the peritoneum [74 (12.3%) in non-bursectomy arm, 73 (12.1%) in bursectomy arm], and bursectomy arm showed a trend of increasing liver metastasis (n = 45, 7.5%) as compared with non-bursectomy arm (n = 33, 5.5%). Six independent poor prognostic factors were identified by multivariable analysis for OS: age ≥ 66 (vs. ≤ 65) (HR, 1.30; 95% CI, 1.04-1.62), macroscopic type 3/5 (vs. type 0/1/2) (1.43; 1.15-1.79), total gastrectomy (vs. distal gastrectomy) (1.44; 1.03-2.02), pT3 (vs. pT1-2) (1.77; 1.17-2.676), pT4 (vs. pT1-2) (3.00; 1.99-4.53), pN1 (vs. pN0) (2.34; 1.52-3.59), pN2-3b (vs. pN0)(4.02; 2.82-5.74) and adjuvant chemotherapy (vs. without chemotherapy) (0.53; 0.42-0.67), but bursectomy was not significant (1.10 0.89-1.36). Conclusions: In the final analysis as well as in the interim analysis, bursectomy was not recommended as a standard treatment for cT3 or cT4 gastric cancer. Clinical trial information: UMIN000003688.