Human papillomavirus (HPV) is the cause of several diseases that affect HIV-infected women, and understanding the effects of HIV coinfection on HPV and anogenital disease has been a core aim of the WIHS since its inception. Clinically, determining the long-term effects of HIV on cervical dysplasia and HPV, the viral cause of cervical cancer, is essential for setting screening and treatment practices in HIV-positive women. Scientifically, studies of HIV-positive women provide unique information about the role of host immunity in HPV infection and cervical tumorigenesis. Via biannual evaluation of the large WIHS cohort, the WIHS HPV Study is intended to be the definitive study of the effects of HIV coinfection on HPV and cervical disease.