Background: During the past few months, many countries encountered high prevalence of COVID-19 infection so it was needed to assess the severity of the disease and mortality in order to control this pandemic .There is a great requirement to detect the changes in different hematological and immunological markers during infection and after recovery from COVID-19 for better understanding of the disease in order to improve its prognosis and its effect on human body. Up to our knowledge, there is no such previous study at Faculty of Medicine Zagazig University (Egypt). Aim: To assess changes in some hematological and immunological parameters after recovery from infection for better understanding of COVID-19 and to study the relationship between the studied parameters with COVID-19 disease severity and patient demographic data . Subjects and methods: This is a prospective comparative cross sectional study. It was conducted in Clinical Pathology and Chest Departments, Faculty of Medicine, Zagazig University Hospitals (Egypt) on forty-five subjects who were previously diagnosed COVID-19 and achieve recovery ,they were divided into 3 groups, in addition to fifteen apparent healthy adult volunteers that matched well with the patients as regard age and sex.Hematological and immunological laboratory tests were measured for all participants. Results: There were statistically significant differences among the studied groups regarding WBCs,D-dimer , most Liver and kidney function tests,Serum Electrolytes (sodium, potassium, magnesium, phosphorous) , Ferritin , IgA, C reactive protein, and antiphospholipid antibodies.and non-significant differences were found as regard tohemoglobin, platelet count , coagulation profile, urea, albumin, bilirubin, LDH,calcium, C3 , C4 , RF, IgM, and IgGhowever IgG and IgM are higher in patients groups than control group Conclusion:Several hematological and immunological parameters may remain affected even after recovery from COVID-19 and the degree of impact on these parameters can be related to the severity of the disease and to the health condition of the patient.