Coinfection with multiple types of human papillomavirus (HPV) and its implications for the development of efficacious HPV vaccines is a subject of great interest. To describe the occurrence of concurrent infection with multiple HPV types and to determine whether genital HPV infection modifies the risk of acquiring a new HPV infection with another HPV type, 1610 subjects were monitored for an average of 4.1 years in Bogota, Colombia. Information on risk factors for HPV infection and cervical cells was collected for detection of HPV DNA of 36 types at study entry and at 6 consecutive 6-month follow-up visits. Clustering or the concurrent acquisition of multiple types occurred more often than would be expected by chance. Subjects with incident HPV-16 or -18 infection had 5-7 times higher odds of acquiring a subsequent HPV-58 infection than subjects not infected with HPV-16 or -18. This might affect the protection conferred by effective HPV vaccines.