In the last few years, cytomegalovirus reactivation has been considered an aggravating factor for septic patients in Intensive Care units. The main objectives of this study were to determine cytomegalovirus reactivation in patients with a diagnosis of sepsis admitted to an intensive care unit, and whether this reactivation was related to the evolution of the patient's clinical condition. The detection of cytomegalovirus DNA was performed by real-time polymerase chain reaction and the concentration of nine cytokines (IL-1α, IL-1β, IL-2, IL-4, IL-6, IL-8, IL- TNF-α, and INFγ) were determined by a Multiplex ELISA technique. Eight of 22 septic patients (36.3%) from the Intensive Care Unit of the Hospital da Luz had cytomegalovirus reactivation. No association was found between cytomegalovirus reactivation and gender, age, length of Intensive Care unit stay, duration of mechanical ventilation, and patient death. No significant differences were found in cytokine concentrations in patients with and without reactivation. However, patients with cytomegalovirus reactivation had a longer hospital stay from Intensive Care unit entry to hospital discharge or patient death (p = 0.025). Despite the low sampling rate, the present study suggests that reactivation is a frequent event in patients diagnosed with sepsis and may be related to prolonged hospital stay in these patients. The overall analysis of the results obtained and the literature review do not support the concept that cytomegalovirus monitoring should be implemented in routine practice, but it seems prudent to wait for further randomized trials using antiviral prophylaxis, before assuming a definitive attitude towards the role of cytomegalovirus in sepsis.