Oral lesions have been recognized as a prominent feature of HIV infection and AIDS since the beginning of the epidemic. This report describes the case of a man with advanced AIDS and a nonpainful but enlarging dorsal tongue soft tissue growth of 6 months' duration. Incisional biopsy showed a red, papillary lesion with koilocytosis consistent with condyloma acuminatum. In situ hybridization and molecular techniques were used to identify human papillomavirus (HPV)-31 sequences in warty tissue. Eighteen months later, the lesion recurred and was reexcised without complication. This case is reported to illustrate that venereal transmission may not be as important in warts of the oral cavity as in HIV-associated anogenital warts, because warts of the oral cavity are rarely associated with HPV types 6, 11, 16, and 18. Instead, they may be present as a result of activation of latent HPV infection or perhaps autoinfection from skin and facial lesions. The carcinogenic potential of oral warts in HIV disease is undefined, as is the role of antiretroviral therapy in controlling HPV-associated oral lesions.