By a reverse transcriptase-polymerase chain reaction assay, we studied the risk of hepatitis G virus vertical infection in seven infants born to women positive for hepatitis G virus ribonucleic acid and hepatitis C virus antibody. Of these, three (42.9%) tested positive for hepatitis G virus ribonucleic acid and two (28.6%) had a carrier state. Intrauterine or birth canal infection seemed much more significant than the infection by breast-feeding.