Recently, some studies demonstrated the association between reactivation of Cytomegalovirus and increase of morbi-mortality in immunocompetent patients admitted to ICUs. To determine the associated factors and consequences of CMV reactivation among Moroccan patients hospitalized in a medical ICU, a prospective and monocentric study was carried out on 72 immunocompetent CMV-seropositive patients admitted to the Medical ICU. The monitoring of CMV by PCR in plasma was carried out at admission and then weekly. The CMV reactivation was occurred in 25 (34.7%) patients. Age of patients (37.7 vs 49.4, p=0.001), median duration of hospitalization before ICU admission (1 vs 4, p=0.006), lower lymphocyte count (1452.98 vs 992.4, p=0.019), increased urea (4.8 vs 13.1, p=0.001) levels and use of oxygen therapy (15 vs 16, p=0.009) were significantly more observed in patients with CMV reactivation upon admission. In term of consequence, the patients with CMV reactivation had a significantly longer length of stay (15 vs 18, p=0.002). In these patients, a last CMV viral load ≥ 3 Log IU/ml is associated with increased risks of mortality. These results demonstrated the association of CMV reactivation with increased morbidity in immunocompetent patients hospitalized in a medical ICU.