BACKGROUND: We estimated the prevalence and incidence of 14 human papillomavirus (HPV) types (6/11/16/18/31/33/35/39/45/51/52/56/58/59) in cervicovaginal swabs, and the attribution of these HPV types in cervical intraepithelial neoplasia (CIN), and adenocarcinoma in situ (AIS), using predefined algorithms that adjusted for multiple-type infected lesions. METHODS: A total of 10,656 women ages 15 to 26 years and 1,858 women ages 24 to 45 years were enrolled in the placebo arms of one of three clinical trials of a quadrivalent HPV vaccine. We estimated the cumulative incidence of persistent infection and the proportion of CIN/AIS attributable to individual carcinogenic HPV genotypes, as well as the proportion of CIN/AIS lesions potentially preventable by a prophylactic 9-valent HPV6/11/16/18/31/33/45/52/58 vaccine. RESULTS: The cumulative incidence of persistent infection with ≥1 of the seven high-risk types included in the 9-valent vaccine was 29%, 12%, and 6% for women ages 15 to 26, 24 to 34, and 35 to 45 years, respectively. A total of 2,507 lesions were diagnosed as CIN or AIS by an expert pathology panel. After adjusting for multiple-type infected lesions, among women ages 15 to 45 years, these seven high-risk types were attributed to 43% to 55% of CIN1, 70% to 78% of CIN2, 85% to 91% of CIN3, and 95% to 100% of AIS lesions, respectively. The other tested types (HPV35/39/51/56/59) were attributed to 23% to 30% of CIN1, 7% to 14% of CIN2, 3% to 4% of CIN3, and 0% of AIS lesions, respectively. CONCLUSIONS: Approximately 85% or more of CIN3/AIS, >70% CIN2, and approximately 50% of CIN1 lesions worldwide are attributed to HPV6/11/16/18/31/33/45/52/58. IMPACT: If 9-valent HPV vaccination programs are effectively implemented, the majority of CIN2 and CIN3 lesions worldwide could be prevented, in addition to approximately one-half of CIN1.