Amniotic fluids from 37 pregnant women with cervical lesions indicative of human papillomavirus (HPV) infection, detected by histology and slot hybridization, were collected at different times during pregnancy and assayed for HPV using the polymerase chain reaction. HPV DNA amplification was obtained in 24 of 37 samples using general primers. Of the 24 positive cases, 13, 5, and 0 were of HPV types 16, 18, and 33, respectively, as determined by using specific anticontamination primers. A correlation between viral DNA amplification and the cervical intraepithelial neoplasia grade was noted. The age of the pregnant women also seemed important for the putative transplacental HPV transmission. At the moment we are not able to evaluate the significance to the fetus of this early contact with the human papillomaviruses; further investigation is necessary to assess the involvement of these viruses in some embryonal and fetal pathology.