Co-infection with EBV and CMV is extremely rare, however reactivation of EBV during an acute infection of CMV has been reported, most cases were observed in pediatric and immunocompromised patients Case presentation: A previously healthy, 33 year old male, was hospitalized in our ward as he came down with a fever of 38.3℃ sustained over the preceding three weeks, fatigue, myalgia and night sweats. The physical examination was consisted with diffused papular abdominal rash and hepatosplenomegaly. Liver function tests were elevated. Serology tests were positive both for Cytomegalovirus (CMV) IgM and Epstein - Barr virus (EBV) IgM. However, they were negative for CMV IgG, Epstein- Barr nuclear Antigen (EBNA) IgG and EBV Viral Capsid Antigen (VCA) IgG. Conclusion: We present a unique case of an adult patient who developed simultaneous acute coinfection of EBV and CMV. However, despite negative laboratory results of IgG, we cannot completely rule out the possibility of reinfection.