To detect human cytomegalovirus (HCMV) DNA, filter paper spotted with peripheral blood from newborns 4 to 7 days after birth was dried and subjected to the polymerase chain reaction (PCR) followed by Southern blot hybridization with a nonradioactive oligonucleotide probe. The detection rates were 25.1% in healthy individuals and 33.0% in low body weight neonates weighing not more than 2500 g at birth, most of whom appeared to have been infected transplacentally or by other means within the uterus. HCMV was detected after only heating the dried blood on the filter paper, and may be applied as a screening method for the early diagnosis of HCMV.