The aim of present study was to examine whether the C-reactive protein (CRP)-based systemic inflammatory response such as the Glasgow Prognostic Score (GPS; a combination of CRP and albumin) offers prognostic value that is superior to the circulating white cellular components as neutrophil/lymphocyte ratio (NLR) or platelet/lymphocyte ratio (PLR) in patients undergoing resection for stage III gastric cancer. The medical records of 324 patients with stage III gastric adenocarcinoma were reviewed. Potential prognosis factors were evaluated with the Kaplan-Meier methodology and multivariable Cox hazards model. An increase of GPS was associated with an increase weight loss, higher NLR, higher PLR, and larger tumor size. On multivariate analysis, only the GPS, tumor-nodes-metastasis staging, and adjuvant chemotherapy were associated independently with disease-free and overall survival. However, the NLR and PLR were not. In subgroup analysis, patients with a GPS of 2 had a significantly poorer median survival (13.70 months) when compared with patients with a GPS of 1 (27.4 months) or 0 (median survival had not been reached) in patients who had received adjuvant chemotherapy. Our study demonstrated that elevated preoperative GPS is superior to circulating white cellular components and was associated with reduced overall and disease-free survival for patients with stage III gastric cancer.