And results showed that PER1 and CRY1 mRNA was significantly decreased in HCMV infection than in the controls (<i>P</i> < 0.0001; <i>P</i> < 0.0001).<h4>Conclusion</h4>PER1 and CRY1 mRNA was significantly decreased in PBMCs from HCMV infected VLBW infants, providing new ideas for studying potential effective therapeutic targets for HCMV infection in VLBW infants. This evidence concerns the gene PER1 and cytomegalovirus infection.