BACKGROUND : Systemic inflammation arising from complex host-tumour interactions is considered the seventh hallmark of cancer. The aim of this study was to assess the clinical feasibility of our newly developed 'lymphocyte-to-C-reactive protein (CRP) ratio' (LCR) and 'lymphocyte CRP score' (LCS) for predicting short- and long-term outcomes in patients with gastric cancer (GC). METHODS : In this observational study, we retrospectively analysed pre-operative LCRs and LCSs from 551 GC patients to elucidate these prognostic value for overall survival (OS) and disease free survival (DFS) and to clarify these predictive value for peri-operative risk of surgical site infection (SSI) in GC patients. RESULTS : Reduced pre-operative LCRs significantly correlated with all of the well-established clinicopathological factors for disease development, including advanced T stage, venous and lymphatic vessel invasion, lymph node/hepatic/peritoneal metastasis, distant metastasis, and advanced tumour-node-metastasis stage. In the short-term outcome, low pre-operative LCR was an independent predictive factor for post-operative SSI. In the long-term outcome, low pre-operative LCR was an independent prognostic factor for OS and DFS, and prognostic impact of pre-operative LCR were verified in patients with metastatic and non-metastatic gastric cancer. Furthermore, our developed scoring system using lymphocyte and CRP (Lymphocyte-CRP Score; LCS) could also demonstrate all of clinical significance in GC patients, and both of LCR and LCS were significantly correlated with various representative nutrition markers, including BMI, PNI, and albumin, in GC patients. CONCLUSIONS : Pre-operative LCR and LCS are clinically feasible nutrition-inflammation markers in GC patients. Assessment of lymphocytes and CRP could aid physicians in determining surgical risk and oncological risk, thus facilitating appropriate peri-operative and post-operative management of patients with GC.