OBJECTIVE To analyze human papillomavirus (HPV) DNA in umbilical cord blood and in placenta, including its cellular localization. METHODS Longitudinal prospective study. METHODS Maternity Unit of Turku University Hospital, and MediCity, University of Turku. METHODS Placental and cord blood samples obtained at delivery from 315 mothers and 311 neonates included in the Finnish HPV Family Study. METHODS HPV testing by nested PCR and sequencing. Tyramide amplified in situ hybridization (ISH) for viral DNA localization in placenta. Correlation to mother's and neonate's oral and genital HPV status and maternal demographic data. METHODS Detection and cellular localization of HPV DNA. RESULTS HPV DNA was detected in 4.2 and 3.5% of placenta and cord blood samples, respectively, including HPV types 16, 6, 83 and 39. In placenta, HPV6 and 16 DNA was localized in syncytiotrophoblasts. Abnormal cytology increased the risk of HPV+ placenta and cord blood. History of genital warts was the only independent predictor of cord blood HPV in multivariate analysis (adjusted OR=4.0, 95% CI: 1.09-14.54, p=0.036). HPV DNA in cord blood increased the risk of genital (OR=4.0, 95% CI: 1.08-14.83, p=0.048) and oral (OR=4.4, 95% CI: 1.17-16.14, p=0.039) HPV DNA carriage of the neonate. HPV+ placenta increased the risk of oral HPV of the neonate (OR=8.6, 95% CI: 2.73-27.13, p=0.0001). Delivery mode did not predict HPV status of the neonate. CONCLUSIONS HPV DNA is detected in placental trophoblasts and umbilical cord blood. The presence of HPV DNA at these sites increases the risk of a neonate testing HPV-positive at birth.