Introduction and importance:Cytomegalovirus (CMV) is a widespread virus, and it affects people of all ages. Infection with this virus causes severe life-threatening disease in immunocompromised patients and newborns. While CMV infection is asymptomatic or present as a mild illness in most cases of immunocompetent patient, it may cause severe diseases in 10% of cases.Case presentation:Here, the authors describe the case of an 11-year-old male presented with an ischemic stroke due to sickle cell disease; who, during hospitalization, developed a prolonged fever. After excluding bacterial infections, infiltrating diseases, rheumatologic diseases, malignancies, and other possible causes, he was diagnosed with CMV infection, which not checked initially, because most cases are asymptomatic.Conclusion:This case highlights the need to consider CMV infection in the differential diagnosis of every case of fever of unknown origin, regardless of the patient’s immune status.