Abstract: Cytomegalovirus (CMV) is a DNA virus that belongs to the β-Herpesvirinae family. It causes asymptomatic infection in immunocompetent adults. The affection of the central nervous system by CMV in immunocompetent patients is uncommon. We reported a case of CMV meningoencephalitis in an immunocompetent 17-year-old patient with no history. The brain MRI shows hyperintensity in the right and the left temporal regions. The detection of cytomegalovirus (CMV) in cerebrospinal fluid (CSF) was performed by the technique of polymerase chain reaction (PCR). The patient was treated by Ganciclovir with good clinical improvement. After six months, the control of the HIV serology was negative and there was no history of any immunosuppressive therapy.