In the present study, we retrospectively studied clinical and laboratory findings associated with cytomegalovirus (CMV) infection in immunocompetent patients. We focused on severe CMV infection. Among 38 patients, five had a severe form of infection: one had meningitis, one had symptomatic thrombocytopenia and three had venous thromboses with pulmonary embolism, a rarely described complication. CMV-induced thrombosis has been reported in immunocompromised patients such as transplant recipients and patients with AIDS. Recent case reports have also described thrombotic phenomena in immunocompetent patients with CMV infection. Our study suggests that venous thrombosis during acute CMV infection is an underestimated complication.