Human papillomavirus (HPV) seems to be involved in head and neck carcinogenesis. To investigate this association, viral presence and expression were analysed by polymerase chain reaction (PCR)-based methods and correlated to tumour localization, clinical-pathological aspects, and alcohol and tobacco exposure in 65 patients. HPV DNA was found in 16 cases (24.6%); the HPV types detected were: HPV16 (10 cases), HPV 6 (3 cases) HPV 33, 35, and 58 (one case each). The tonsil was the location with the highest HPV positivity (6/8, 75%). This percentage was significantly higher than that found in tumours from any other site (P<0.01). Viral transcripts of early regions were detected in all HPV16 positive tumours. HPV status was not related to age, gender, tumour stage or grade, and use of alcohol and/or tobacco. The results suggest that HPV16 is actively involved in the genesis of a subset of head and neck cancers and that the tonsillar localization may be considered a hot spot for viral transformation.