The aim of this prospective study of 162 recipients of bone marrow transplantation (BMT) was to evaluate the use of DNAemia detection by semi-nested PCR for the diagnosis of human cytomegalovirus (HCMV) infection and HCMV disease. We compared the results obtained for DNAemia with those obtained for viremia, using the shell vial assay. Patients were divided in three groups, according to BMT type (allogeneic or autologous) and date of transplant; 876 DNAemia/viremia pairs were analyzed and the overall concordance between the two tests was 97.5%. Discrepancies between the two tests were essentially due to the earlier positivity of DNAemia. Among the 10 patients with positive DNAemia episodes, 9 developed HCMV disease. DNAemia was more sensitive than viremia for HCMV disease diagnosis, while viremia had a higher positive predictive value. DNAemia appeared easily adaptable to routine laboratory use, less expensive and more informative than viremia. This study shows that DNAemia is a method that can replace viremia detection, allowing HCMV infection and disease follow-up of recipients of allogeneic BMT during the first year after BMT.