Human herpesviruses, especially cytomegalovirus and Epstein Barr virus type-1, occur with higher frequency in subgingival specimens from periodontitis lesions than from healthy/gingivitis sites. Little or no information is available on the relationship between herpesvirus 6 (HHV-6), herpesvirus 7 (HHV-7) and herpesvirus 8 (HHV-8) and periodontal disease. This study determined the periodontal occurrence of HHV-6, HHV-7 and HHV-8 in 21 HIV-seropositive and 14 HIV-negative adults affected by periodontitis. Gingival biopsy specimens and paper-point samples of subgingival plaque were collected from sites showing 5 mm or more in probing depth. Nested polymerase chain reaction methodology was employed in herpesvirus identification. In the HIV-seropositive periodontitis group, 90% of gingival biopsies and 62% of subgingival plaque samples revealed at least one of the test viruses. HHV-6 occurred in 71%, HHV-7 in 67% and HHV-8 in 24% of gingival biopsies. In the HIV-negative adult periodontitis group, 43% of gingival biopsies showed at least 1 of the test viruses, with HHV-6 present in 21% and H HV-7 in 29% of gingival biopsies and with no detection of HHV-8. The combined occurrence of the 3 test herpesviruses was significantly higher in HIV-seropositive than in HIV-negative adult periodontitis patients (p = 0.008). The human periodontium might constitute a site of infection or reservoir for HHV-6, -7, -8.