Background: NLR has historically been used as a predictor of morbidity and mortality in patients with COVID -19.Inflammatory markers serum ferritin, C-reactive protein (CRP) and serum LDH have been reported to be significantly associated with the high risks of the development of severe COVID19. Aims: To correlate with total lymphocyte count (TLC) and Neutrophil lymphocyte ratio (NLR) in assessing the clinical course of COVID 19 and to study the role of inflammatory markers in assessing the severity and clinical course of COVID 19. Methods: The study was done as a cross sectional study among 519 patients who admitted in Trichy SRM medical college hospital and research centre. All adults of both sexes diagnosed with COVID 19 were included in study by consecutive sampling and patients with known chronic inflammatory conditons, autoimmune disorders, malignancy were excluded from the study. The total lymphocyte count and neutrophil lymphocyte ratio were recorded and blood CRP, serum LDH, ferrtin, D dimer were done and correlated with the disease severity and clinical course of COVID. Results: Among 518 patients, 257(49.6%) patients were in the age group of 46 to 65 years and 309 (59.7%) patients were males and 209 (40.3%) were females. Neutrophil Lymphocte ratio was 3-2.5 in (30.9%) patients. Duration of stay in hospital was 11-14 days for 82 patients in that C reactive protein was positive for 55(67%) patients, serum ferritin range was 270-700 in 38(46.4%) patients, serum LDH range was 250-500 in 42(51.2%) patients and D-dimer was above 500 in 19(23.2%) patients. Conclusion: NLR and higher inflammatory markers correlates well with severity of disease and duration of hospitalization in COVID 19 patients.