The severe acute respiratory syndrome-coronavirus 2 (SARS-CoV-2) spread rapidly all over the world in late 2019 and caused critical illness and death in some infected patients. This study aimed at examining several laboratory factors, especially inflammatory and immunological mediators, to identify severity and mortality associated biomarkers. Ninety-three hospitalized patients with confirmed coronavirus disease 2019 (COVID-19) were classified based on disease severity. The levels of biochemical, hematological, immunological, and inflammatory mediators were assessed, and their association with severity and mortality were evaluated. Hospitalized patients were mostly men (77.4%) with an average (standard deviation) age of 59.14 (14.81) years. The mortality rate was significantly higher in critical patients (85.7%). Increased serum levels of blood sugar, urea, creatinine, uric acid, phosphorus, total bilirubin, serum glutamic-oxaloacetic transaminase, serum glutamic-oxaloacetic transaminase, lactic dehydrogenase, C-reactive protein, ferritin, and procalcitonin were significantly prevalent (p=0.002, p<0.001, p<0.001, p=0.014, p=0.047, p=0.003, p<0.001, p<0.001, p<0.001, p<0.001, P<0.001, and p<0.001, respectively) in COVID-19 patients. Decreased red blood cell, hemoglobin, and hematocrit were significantly prevalent among COVID-19 patients than healthy control subjects (p<0.001 for all). Troponin-I, interleukin-6, neutrophil/lymphocyte ratio (NLR), procalcitonin, and D-dimer showed a significant association with the mortality of patients with specificity and sensitivity more than 60%. Age, sex, underlying diseases, blood oxygen pressure, complete blood count along with C-reactive protein, lactic dehydrogenase, procalcitonin, D-dimer, and interleukin-6 evaluation help to predict the severity and required management for COVID-19 patients. Further investigations are highly recommended in a larger cohort study for validation of the present findings