Investigations of serum antibody status to the five human herpesviruses--herpes simplex virus type 1, herpes simplex virus type 2, cytomegalovirus, Epstein-Barr virus, and varicella-zoster virus--were conducted on 197 Navajo children, aged 1-15 years, at a reservation pediatric outpatient clinic in Crownpoint, New Mexico, from 1981-1984. To determine the severity of infection with the human herpesviruses, the authors reviewed lifetime medical records of 166 of the children for evidence of herpesvirus-related diseases, and to illuminate potential modes of transmission of the viruses, they completed home interviews on the families of 87 of the children. The investigation showed that the children had a high prevalence of antibody to herpes simplex virus type 1 (73% of total sample), cytomegalovirus (78%), Epstein Barr virus (98%), and varicella-zoster virus (77%), and that prevalence tended to increase with age. None of the children demonstrated herpes simplex virus type 2 antibodies. The medical records showed that 30% of the children had suffered from gingivostomatitis prior to the study. When age was controlled for, the study showed herpes simplex virus type 1 seropositivity to be associated with children who slept in the same bed as their parents during infancy (p = 0.003) and with frequent attendance at community events (p = 0.02); cytomegalovirus seropositivity was shown to be associated with female sex (p = 0.007) and with living in a traditional Navajo dwelling (p = 0.007). The Navajo children also demonstrated a greater frequency of symptomatic oral herpes simplex virus type 1 infection than is usually recorded. The findings suggest a relation between certain patterns of cultural behavior and transmission of herpesvirus infections.