Aims and objectiveWe addressed the determinants and of the factors associated with neutrophil lymphocyte (N/L) ratio in patients with COVID 19 infection and its associates with mortality.Methods: 163 participants with COVID 19 infection who were treated in the clinic and ICU were evaluated retrospectively. Demographics, laboratory findings, hospitalization duration, baseline Who and Charlson scores and mortality were assessed.Results: 163 participants 44.8 % women were evaluated retrospectively. Mean age of the patients was 55.8 ± 16.8. Mortality observed in 14.1 % of the participants. There were significant difference between the groups regarding the laboratory findings, hospitalization duration, comorbidity indexes and admission to ICU in deceased group when compared to survivors.There was a significant difference between the patients who were admitted to intensive care unit (ICU) and who were not regarding the neutrophil lymphocyte (N/L) ratio (9.56 ± 1.68 & 3.47 ± 0.31; p=0.001). there was also significant difference between the adults who died and survived (9.72 ± 1.87 & 4.03 ± 0.44; p=0.007). There were significant associations between N/L levels and CRP (OR = 0.441, 95 % CI = 0.019 -0.058; p = <0.001) D-dimer (OR=0.566, 95 % CI = 0.821 -1.541; p<0.001) as well as Who score at baseline (OR = 0.309, 95 % CI =0.990 -3.604; p<0.001).  Conclusion: Neutrophil/lymphocyte ratio is associated with CRP, D-dimer and Who score at baseline but not with the mortality.