Nineteen samples of DNA from squamous cell carcinoma of the upper aerodigestive tract were analyzed by Southern blot hybridization for the presence of human papillomavirus (HPV) DNA. Two samples of DNA contained HPV 16 DNA or its homologous sequence. In one maxillary carcinoma, the sequences homologous to HPV 16 were detected. In one tonsillar carcinoma, HPV 16 sequence was also shown to be present. The patients positive for HPV DNA were female and had neither smoking nor drinking habits. These results indicate that HPV infections may play a role in the development of some types of squamous cell carcinomas of the upper aerodigestive tract.