Human papillomavirus (HPV) vaccines have been shown to be both highly effective and safe, and there is now considerable enthusiasm among healthcare providers to use the vaccines to reduce the burden of HPV-associated disease in women. When considering who should be vaccinated, it is important that providers understand the complex relationships between age and HPV infections. HPV infections and cervical cancer have a widespread impact on society. Cervical cancer is the cause of a significant amount of morbidity and mortality throughout the world, making it crucial to implement prophylactic HPV vaccines to prevent cervical cancer. Nationally, the target group for vaccination is pre-adolescent females who have not been sexually active or who have recently become sexually active. In the United States, the Advisory Committee on Immunization Practices recommends HPV vaccination for females aged 11 to 12 years. "Catch-up" vaccination of females aged 13 to 26 years who have not been previously vaccinated or who have missed a vaccination is also recommended, as females within this age group have the highest prevalence of HPV infection. Vaccination can still benefit females over the age of 26 years who have not been previously exposed to HPV 6, 11, 16, or 18 and those who may have new sexual partners in the future. This review discusses the various considerations that should be addressed when making recommendations of who should be vaccinated against HPV. © 2008 Elsevier Inc. All rights reserved.