<p>This study aimed to evaluate prognostic value of resting heart rate (RHR) in patients with gastric cancer. We analyzed 1,561 patients who underwent radical gastrectomy at Severance Hospital, Korea. RHRs were measured after surgery, and detailed medical, treatment, and lifestyle information was collected. Cox regression models were used to estimate the hazard ratios (HRs) and 95% confidence interval (95% CI) for the association between postoperative RHR and prognostic outcomes. During a median of 4 years of follow-up, we identified 174 total deaths, 92 major complications (within 30 days), 186 recurrences, and 106 gastric-cancer-specific deaths. In multivariable-adjusted models, HRs (95% CI) per 10 beats per minute increase in RHR were 1.18 (1.07–1.31) for all-cause mortality, 1.45 (1.33–1.59) for major complication within 30 days, 1.13 (1.02–1.26) for recurrence, and 1.07 (0.93–1.24) for gastric cancer-specific mortality. We consistently observed that higher postoperative RHR is associated with poor prognostic outcomes regardless of demographics, lifestyle, and cancer stage in patients with gastric cancer. In conclusion, an elevated postoperative RHR was associated with an increased risk of all-cause mortality, major complications, and recurrence in patients with gastric cancer. RHR can potentially be used to predict the prognosis of patients with gastric cancer.</p>