Early risk classification of coronavirus disease 2019 (COVID-19) patients admitted to hospital is a critical key for providing optimal interventions. We investigated whether neutrophil-to-lymphocyte ratio (NLR) levels and other inflammatory and coagulation markers could be predictors for the severity and mortality of hospitalized COVID-19 patients. This cross-sectional study included 155 COVID-19 patients diagnosed by the reverse transcription polymerase chain reaction (RT-PCR) using oropharyngeal swabs. All patients had clinical examination, routine laboratory investigation, and chest computerized tomography scan. O2 saturation, serum D dimer, C reactive protein (CRP), erythrocyte sedimentation rate (ESR), lactate dehydrogenase (LDH), and serum ferritin were assessed. NLR can predict the adverse outcome (e.g., disease deterioration and shock) at cut-off 6.65, with 92% sensitivity and 20.7% specificity. LDH at cut-off value of 364.5 had 79.3% sensitivity and 47% specificity. Ferritin at a cut-off value of 1036 had 60.9% sensitivity and 60.6% specificity. NLR alone was not an independent predictor for ICU, however, combining NLR with ferritin and LDH predicted the need for ICU. Total leucocytic count (TLC), neutrophil count, lymphocytic count, D dimer, and CRP were independent predictors for the need of ICU admission (P < 0.05). Admitted patients to ICU and dead patients had higher COVID-19 Reporting and Data System, length of stay, LDH, and ferritin and lower O2 saturation than non-admitted and alive ones. We concluded that NLR with ferritin and LDH markers had higher degree of sensitivity and specificity in detecting adverse outcomes in COVID-19 patients. Other inflammatory biomarkers such as TLC, neutrophil, lymphocyte, D dimer, and CRP were predictive in this case.