Baseline serum samples from 2815 human immunodeficiency virus (HIV)-positive and 963 HIV-negative women enrolled in 2 cohort studies were tested for immunoglobulin G antibodies to human papillomavirus type 16 (HPV-16) capsids. HPV-16 seropositivity was associated with lifetime number of sex partners (P<.001) among both HIV-positive and HIV-negative women. Approximately 50%-60% of HPV-16 DNA-positive women were HPV-16 positive. HPV-16 seropositivity was associated with HIV infection; however, after adjustment for baseline cervical HPV infection and disease, the association disappeared. Thus, the high seroprevalence of HPV-16 among HIV-positive women may be explained by a high prevalence of HPV of all types. Approximately 50% of HIV-positive women had serological evidence of prior HPV-16 infection, but only approximately 5% had an HPV-16 cervical infection at baseline. Despite the higher prevalence of HPV infection in this group, most HIV-positive women are able to control HPV-16 replication at the cervix, and reactivation, if it occurs, is not very common.