We retrospectively studied biopsy specimens obtained from 16 patients who had carcinoma of the tonsil or nasopharynx. Polymerase chain reaction testing detected the presence of human papillomavirus (HPV) in 13 samples (81.3%)--six tonsillar and seven nasopharyngeal. Eleven of the 13 positive samples (84.6%) contained HPV subtype 31. We believe that this is the first report of the presence of HPV subtype 31 in these carcinomas. In addition to the significant association between tonsillar and nasopharyngeal cancer and HPV, our analysis of descriptive variables confirmed the association between the incidence of these neoplasms and poor oral hygiene and low socioeconomic status in older adults.