Recently, increasing attention is being paid to the viral etiology of atherosclerosis (AS). Human cytomegalovirus (HCMV) is thought to be the most possible etiological factor of AS. In our study, artery vascular tissue specimens derived from 75 patients with AS were studied for detection of HCMV immediately early (IE) and later (L) gene fragments by polymerase chain reaction (PCR) and in situ hybridization; sera collected from the same patients were examined for HCMV specific IgG and IgM by enzyme-linked immunosorbent assay (ELISA). Twenty two normal arterial tissues and sera were used as controls. We found that the positive rate of HCMV L and IE gene fragments were significantly higher in AS patients than those in controls. HCMV DNA were mainly observed in nucleus of endothelial cells and muscularis under intima as well as smooth muscle of media of AS area, rarely found in controls. These results suggested that HCMV infection may relate to the pathogenesis of AS; and the artery itself may be the site of HCMV latency. In addition, higher levels of HCMV IgG and IgM were found to be associated with virus persistence, indicating that a periodically active latent infection or a continuously active infection is presented in AS patients.