Background/Aim: Lymphocyte-to-C-reactive protein ratio (LCR) is a useful biomarker for predicting the prognosis of various cancers. This study examined the effect of LCR on the oncological prognosis of patients with gastric cancer who underwent curative resection at our institution and considered the mechanisms involved. Patients and Methods: In this retrospective cohort study, 258 subjects were selected from the medical records of patients who underwent curative resection for gastric cancer at Yokohama City University between 2005 and 2020. The LCR was calculated using the following formula: LCR=lymphocyte count (number/μl)/C-reactive protein (mg/dl). Results: The cutoff value for LCR was set at 9,000, and 258 patients were classified into the LCR-low (<9,000) (58 patients) and LCR-high (>9,000) (200 patients) groups. The overall survival (OS) and recurrence-free survival (RFS) rates of the two groups were compared. The 5-year overall survival rate was 54.2% in the LCR-low group and 75.2% in the LCR-high group (p<0.001), and a multivariate analysis showed that it was a useful prognostic factor [hazard ratio (HR)=1.744, 95% confidence interval (CI)=1.009-3.014, p=0.046]. In addition, with regard to RFS, there was a significant difference in the 5-year RFS between the LCR-low group (50.4%) and the LCR-high group (72.3%) (p<0.001). Regarding the comparison of the postoperative clinical course between the two groups, the peritoneal recurrence rate was 24.1% in the LCR-low group and 7.5% in the LCR-high group (p<0.001). Conclusion: Preoperative LCR is a useful prognostic factor for predicting the oncological prognosis of patients with gastric cancer undergoing curative resection. Thus, the LCR may be a useful tool for the treatment and perioperative management of patients with gastric cancer.