The challenges of the journey from target identification through development of a prophylactic quadrivalent human papillomavirus (HPV) vaccine have been met in Gardasil. Cervical cancer is the second leading cause of cancer-related death in women worldwide. Approximately 70% of cervical cancer is caused by infection with HPV types 16 and 18 and approximately 90% of genital warts are caused by HPV types 6 and 11. The quadrivalent HPV vaccine was generated by expression of the major capsid protein (L1) of HPV types 16, 18, 6 and 11 in yeast. L1 proteins self assemble into pentamer structures and these pentamer structures come together to form virus-like particles (VLPs). The VLPs are antigenically indistinguishable from HPV virions. The VLPs contain no viral DNA and therefore the vaccine is non-infectious. Gardasil is composed of VLPs of HPV types 16, 18, 6 and 11 conjugated to a proprietary amorphous aluminum hydroxyphosphate sulfate adjuvant. The results of a rigorous clinical program have demonstrated that the vaccine is safe and highly efficacious in preventing dysplasias, cervical intraepithelial neoplasias (CIN 1-3) the precursors of cervical cancer and external genital lesions caused by vaccine-HPV types. In conclusion, Gardasil addresses a major medical need, that is, reduction of HPV-related disease including cervical cancer as a safe, immunogenic, and highly efficacious vaccine.