Chronic lymphocytic leukemia and non-Hodgkin lymphoma (NHL) are types of Chronic Lymphoproliferative Disorders (CLPDs) that develop from mature B cells. Immunophenotyping and characteristic morphology are used to diagnose chronic lymphocytic leukemia. some people with chronic lymphocytic leukemia have an unusual immunophenotype which increases the probability that they may have mantle cell lymphoma (MCL), a lymphoproliferative disorder unrelated to chronic lymphocytic leukemia. To distinguish between MCL and chronic lymphocytic leukemia, our study was made and involved 70 patients who were attending the clinical pathology department at Sohag University Hospital. These patients were split into 25 cases of MCL, 25 cases of chronic lymphocytic leukemia, and 20 age- and sex-matched controls. Using flow cytometry, the expression of CD200 was assessed in bone marrow aspirate samples obtained from these patients. We found that CD200 helps distinguish between chronic lymphocytic leukemia and MCL since our data demonstrate that 24 cases of chronic lymphocytic leukemia were CD200 positive, whereas 25 cases of MCL and 20 controls were CD200 negative.