Purpose: The aim of our study is to investigate the prognostic value of Neutrophil-to-lymphocyte ratio (NLR), monocyte-to-lymphocyte ratio (MLR), and platelet-to-lymphocyte ratio (PLR) in determining mortality in patients hospitalized for intensive care unit (ICU) sepsis.
 Materials and Methods: This study retrospectively evaluates all patients hospitalized with sepsis in our ICU between February 2017 and April 2018. In addition to the demographic and clinical characteristics of the patients, complete blood count parameters were also recorded. Demographic and clinical characteristics, mainly NLR, MLR and PLR results, and other laboratory results of patients with sepsis were compared between the ones with and without mortality. 
 Results: Four hundred and eleven patients were included in the study. 55.7% (229/411) of patients with sepsis died and 44.3% (182/411) were discharged alive. NLR, MLR and PLR were higher in the group with mortality compared to the survivor group. The cut-off value for predicting mortality in patients with sepsis was 9.2 for NLR, ≥0.8 for MLR, and ≥187.3 for PLR. The area under the curve (AUC) value for NLR was 0.825, the AUC value for MLR 0.835 and the AUC value for PLR was 0.720.
 Conclusion: High NLR, MLR and PLR values are associated with mortality in sepsis patients hospitalized in ICU, and the most significant parameter for mortality indicator among the three rates was found to be MLR with the highest AUC value.