Our findings document the substantial number of high-risk HPV infections that Hybrid Capture 2 testing would detect among women presenting for cervical screening at STD, family planning, and primary care clinics in the United States. The overall prevalence of 23% shown by Hybrid Capture 2 testing and the large number of infections across demographic groups, clinic types, and cities is indicative of the high prevalence of high-risk HPV (although most infections will not result in cervical disease, particularly among adolescents [10–11]). Of age, race, ethnicity, clinic type, and city categories, high-risk HPV prevalence differed most by age (range, 6% to 35%). The observed distribution of steadily decreasing high-risk HPV prevalence across increasing age groups is consistent with that observed in other studies in the United States and other developed countries with cervical screening programs (12). In contrast, other countries exhibited U-shaped prevalence curves or flat curves (that is, high HPV prevalence with no decrease in older groups). Observed variations are most likely due to differences in the availability of cervical screening programs, in incidence of HPV infections, and in sexual behaviors. In contrast to known epidemiologic associations between race and other sexually transmitted infections (13–15), the age-adjusted prevalence of high-risk HPV infection did not vary substantially by race (range, 20% to 24%, excluding the prevalence of 32% observed among multiracial women) or ethnicity (range, 20% to 24%) but did vary more by clinic type (range, 17% to 26%, adjusted for age and city). The range in prevalence across cities was 19% to 28% (adjusted for age and clinic type). Analyses are planned to further evaluate these observed differences.