Advanced gastric cancer has a poor prognosis because of advanced gastric cancer is prone to metastasis. It is urgent for us to find an indicator to predict the prognosis of gastric cancer in a timely fashion. Research has revealed that inflammation has an important role in predicting survival in some cancers. The purpose of this study was to evaluate the significance of neutrophil-to-lymphocyte ratio (NLR) and platelet-to-lymphocyte ratio (PLR) on the prognosis of metastatic gastric cancer (GC). This was a retrospective review of 110 patients were at presentation diagnosed with stage IV metastatic GC and all patients received palliative chemotherapy between January 2012 and January 2016 at the Affiliated Hospital of Qingdao University. Pretreatment NLR and PLR, as well as clinicopathological characteristics were collected. Patients were divided into high and low groups according to the cutoff values for NLR and PLR. The Kaplan–Meier method was applied to estimate the overall survival (OS) and the Cox proportional hazards model to evaluate the related risk factors for OS. All tests were 2-tailed and a P < .05 was considered to indicate a statistically significant difference. One hundred ten patients were enrolled. Eighty-four patients were men, 24 patients were women, 61 patients were ≥65 years of age, and 49 patients were <65 years of age. The Eastern Cooperative Oncology Group (ECOG) score of most patients (n = 107) ranged from 0 to 1. Ten patients were human epidermal growth factor receptor 2 (HER2)-positive. Seventy-one patients presented with an elevated carcinoembryonic antigen (CEA) level and 49 patients had an elevated Carcinoembryonic 199 (CA-199) level. Fifty-two patients received first-line chemotherapy only. Nineteen patients received third-line or greater chemotherapy. One hundred patients chose dual drug chemotherapy. The median duration of follow-up was 11.6 months. Based on the receiver operating characteristic (ROC) curve, the optimal cut-off value for NLR and PLR was 2.48 and 143.39. Patients with high NLR and high PLR had poor overall survival compared with those who had low NLR and low PLR ( P < .001 and P = .013, respectively). In univariate analysis, old age ( P = .013), liver metastasis ( P = .001), >1 metastatic sites ( P = .028), higher NLR ( P = .000), and higher PLR ( P = .014) were identified as poor prognostic factors associated with OS. Our multivariate analysis had indicated that high NLR (hazard ratio [HR]: 1.617, 95% CI: 1.032–2.525, P = .036) and peritoneal metastasis (HR: 1.547, 95% CI:1.009–2.454, P = .045) was independent prognostic factors for overall survival; however, the PLR was not shown to be an independent prognostic factor. Our study suggested that the pretreatment NLR can be used as si...