Objective: To describe the frequency and the clinical and laboratory characteristics of infections with cytomegalovirus (CMV), Epstein-Barr (EBV) and herpes simplex virus 1 and 2 (HSV 1 and HSV 2) in central nervous system in both immunocompetent and immunocompromised patients. Methods: A total of 204 cerebrospinal fluid samples were tested for CMV, EBV or HSV 1 and 2 using real time PCR as a molecular diagnostic tool for detection of infection. Results: Sixteen percent of cerebrospinal fluid was positive for at least one of the viruses, and Epstein Barr virus was detected in 22.8% of cases, which is above the infections caused by HSV and CMV. 61.9% of positive patients had some form of immune compromise.