Myelodysplasia and severe thrombocytopenia in association with cytomegalovirus (CMV) infection in immunocompetent adults have rarely been reported. We describe a previously healthy man who developed severe thrombocytopenia with myelodysplastic changes of bone marrow and multiple autoimmune abnormalities following CMV infection. We also discuss possible mechanisms leading to myelodysplasia and thrombocytopenia in CMV infection. We believe that CMV infection should be considered in the differential diagnosis of myelodysplasia and acute thrombocytopenia.