Human cytomegalovirus (CMV) is a major cause of severe disease in HIV-infected persons and some findings suggest that it may accelerate HIV disease. In this study, a total of 621 blood samples from patients with LAS-ARC and AIDS were analysed in parallel for CMV and HIV-I antigenaemias. Results indicate that the presence of CMV antigenaemia and the presence of HIV-I p24 in the blood are highly correlated statistically and encourage other studies on the role of CMV in the evolution of AIDS. In a smaller group of cases, CMV was also isolated from saliva and/or urine. The correlation with HIV replication was positive (although much lower) with CMV detected in saliva and completely negative with CMV isolated from urine.