 Infection with human papillomavirus HPV has been clearly established as the central cause of cervical cancer. This Phase IV, observer-blind study is designed to evaluate the safety and immunogenicity of CervarixTM in HIV infected females aged 15 to 25 years as compared to Mercks HPV vaccine Gardasil. For comparative purposes, a group of HIV negative females will also be evaluated. All subjects will receive the HPV vaccine either CervarixTM or Gardasil according to a three-dose schedule Day 0, Week 6, Month 6. 