Aim: COVID-19 (coronavirus disease 2019) pneumonia is a serious condition with high mortality and morbidity. Tools are needed for effective diagnosis and better prediction of prognosis in the course of this disease. This study aimed to compare the effectiveness of the MuLBSTA (Multilobular infiltration, hypo-Lymphocytosis, Bacterial coinfection, Smoking history, hyper-Tension and Age) score with blood parameters, SOFA (Sequential Organ Failure Assessment), and APACHE II (Acute Physiology and Chronic Health Evaluation II) scores, and to investigate its significance in predicting 28-day mortality in patients diagnosed with COVID-19 and followed up in the intensive care unit (ICU).Material and Method: This study included 312 patients admitted to ICU for COVID-19 infection. SOFA, MuLBSTA and APACHE-II scores of patients were estimated at ICU admission. Demographic data and laboratory results of patients were retrospectively reviewed.Results: Of the 312 patients included in the study, 58.7% (n=183) were male and 41.3% (n=129) were female. The AUC value was 0.863 for the SOFA score and 0.843 for the MuLBSTA score. The MuLBSTA score was positively correlated with the neutrophil-to-lymphocyte ratio (NLR) and platelet-to-lymphocyte ratio (PLR), while it was negatively correlated with the lymphocyte-to-monocyte ratio (LMR). Patients were divided into two groups as high-risk and low-risk, considering a cut-off value of 12 for the MuLBTSA score. The survival time of patients with a high-risk MuLBTSA score was 12±0.78 days, while the survival time of patients with a low MuLBTSA score was 22.8±1.3 days.Conclusion: The combined use of the MuLSBTA score, SOFA score, and NLR after ICU admission for COVID-19 pneumonia will be more effective in predicting mortality.