SUMMARY. The objectives of the present study were to assess the possible predictors of COVID-19 severity and duration of hospitalization and to identify the possible correlation between patient parameters, disease severity and duration of hospitalization. The study included retrospective medical record extraction of previous coron avirus COVID-19 patients in Basra hospitals, Iraq from March 1st and May 31st, 2020. The information of the participants was investigated anonymously. All the patients’ characteristics, treatments, vital signs and laboratory tests (hematological, renal and liver function tests) were collected. The analysis was conducted using the SPSS (version 22, USA). Spearman correlation was used to measure the relationships between different blood lab data predictors, the disease severity and the duration of hospitalization. The Kruskal Wallis Test was used to measure the difference in the severity of the disease according to the serum ferritin level. Overall, 499 patients were includ ed in the current study: 58.4% were female and 41.6% were male. Nearly half of the patients had chronic disease particularly diabetes mellitus (20.8%) and hypertension (23.6%). With regards to hematological tests, there was a significant correlation between lymphocyte level and disease severity, duration of hospitalization, ferritin, platelets and neutrophil level. In addition, serum urea and creatinine have significant (p-value < 0.05) positive correlation with the disease (COVID-19) severity. Similarly, there is a significant difference in the severity of the disease ac cording to the ferritin level. Thus, patients with more severe symptoms had higher level of blood ferritin. Further more, patients with co-existing diseases have experienced more severe COVID-19 symptoms. This indicates that, lymphocyte and ferritin levels are good predictors of COVID-19 severity. This study finding indicated that evalua tion of blood laboratory indices (CBC including lymphocytes and ferritin) and renal/liver function parameters in the beginning of the COVID-19 could predict the severity and duration of hospitalization. In addition, patients with multiple comorbidities are at higher risk of longer days of hospitalization. An early attention to the patient parameter and lab data may help in tailoring treatments and promote possible interventions to triage hospitaliza tion and save more lives particularly Iraqi might experience a second wave of the pandemic.