ABSTRACT: To evaluate the prognostic significance of neutrophil-to-lymphocyte ratio (NLR), platelet-to-lymphocyte ratio (PLR), lymphocyte-to-monocyte ratio (LMR), and prognostic nutritional index (PNI) and other clinicopathological factors in patients undergoing curative resection of colon cancer.183 patients with histologically proven colorectal cancer who had undergone potentially curative resection between 2010 and 2016 at Ankara Numune Training and Research Hospital were retrospectively analyzed and clinicopathological characteristics included age, sex, tumor type, grade, size and localization, the number of metastatic and total number of lymph nodes removed, vascular and perineural invasion of the tumor, TNM stages, tumor marker levels (CEA, CA19-9, AFP, CA-125, CA15-3), complete blood counts, albumin levels, overall survival (months), NLR, PLR, LMR and PNI ratios were retrospectively reviewed and analyzed from the electronic database. The primary outcome measure was overall survival.Regarding overall survival, on univariate analysis the following variables were significantly associated with poor outcome following resection: T-stage (P = 0.037), lymph node invasion (P = 0.037), cancer stage (P = 0.034), CEA (P = 0.042), CA19-9 (P = 0.004), and PNI (P = 0.001). To evaluate the independent prognostic value, multivariate Cox proportional hazard analysis to control for other prognostic factors was used. Using cancer-specific death as an end point for NLR, PLR, LMR, PNI and CA19-9 the optimal cut off values were calculated by ROC analysis. Regarding overall survival, on multivariate analysis high CA19-9 (HR = 1.001, 95%CI: 1.00-1.002, P = 0.012) and low PNI (HR = 0.938, 95%CI: 0.891-0.987, P = 0.014) were the only variables independently associated with shortened overall survival. Patients with a PNI < 35 had a median OS of 52.25 mo. In contrast, patients with an PNI > 35 had a median OS of 66 mo. Patients with a CA 19-9 < 17 had a median OS of 66 mo and in patients with a CA19-9 > 17 had a median OS of 53.76 mo.This study shows that decrease in the PNI and increase in CA 19-9 is associated with poor survival in patients with resectable colon cancer.