PURPOSE: Immunosuppression is a characteristic of cancer recurrence after curative resection. The neutrophil-to-lymphocyte ratio (NL ratio) in peripheral blood is associated with immune function. However, it is not clear whether the postoperative NL ratio is a predictor for cancer relapse after resection. Thus, we investigated the effectiveness of the short-term postoperative NL ratio in the prediction of disease recurrence within 5 years after stomach cancer surgery by a retrospective chart review. METHODS: Ninety-three patients with stomach cancer were enrolled. Significant risk factors for cancer recurrence were determined by multivariate Cox regression. Independent variables to increase the NL ratio to >7.7 by postoperative day (POD) 3 were examined by multivariate logistic regression analysis. RESULTS: The 5-year risk of cancer recurrence after gastrectomy was 4.2 times higher for patients with a POD3 NL ratio of >7.7 (P = 0.005), 3.4 times higher for normal-weight patients compared with overweight patients (P = 0.008), and 20 times higher for stage III compared with stage 0 according to the tumor-node-metastasis cancer staging system (P = 0.003). The surgical duration (hours) increased the chance of high NL ratio >7.7 (odds ratio, 2.5; P = 0.006). CONCLUSION: The postoperative NL ratio, especially the POD3 NL ratio, predicts long-term recurrence after stomach cancer surgery.