Human papillomavirus (HPV) vaccines are available in the United States and around the world to prevent HPV-associated diseases including cervical cancer and genital warts. HPV vaccination is currently recommended for adolescents: target ages for routine and catch-up vaccinations vary by country. Because the time from vaccination to cancer development can be several decades, many studies are evaluating more immediate outcomes. In the 4 years since the vaccine was introduced, reductions in HPV vaccine type prevalence and genital warts have been reported in young females in the United States and other countries. Many questions remain about the long-term impact, but the initial studies show promising results for the relatively new HPV vaccine.