There are many methods of detecting human cytomegalovirus (HCMV) infection. So far, the quantitative polymerase chain reaction (PCR) has been very useful not only in aiding in the diagnosis of HCMV but also in determining the severity and predicting HCMV infection. However, it is time-consuming and labor intensive. Real-time PCR (RT-PCR) is an exception, for it allows rapid quantification of HCMV DNA load. Our group used this method for detecting and monitoring HCMV and compared it with the diagnostic criterion recommended by the Pediatric Branch of Chinese Medical Association, in 45 children suspected of having HCMV infection. The response to two types of antiviral treatment on HCMV DNA load was also monitored in HCMV hepatitis cases. RT-PCR was positive in 30 cases while the diagnostic criterion, which includes enzyme-linked immunosorbent assay (ELISA) and/or conventional PCR, was positive in 32 cases. The decrease in the HCMV DNA load was achieved earlier in the modified treatment group compared with the conventional treatment group. A 103 copies/ml of HCMV DNA load of is a useful cut-off value in predicting patients who will have symptoms of the disease. RT-PCR can be used not only in detecting HCMV but also in monitoring response to antiviral treatment and risk of having symptoms of the disease.