Background: Human papillomavirus (HPV) is sexually transmitted and causes cervical cancer. Although HPV can infect men and women, little is known about infection in men. Specifically, the prevalence of type-specific HPV infection and the distribution of infections by anogenital anatomic site in men are incompletely characterized. Methods: We tested 463 men ages 18 to 40 years for HPV at the glans/corona, penile shaft, scrotum, urethra, perianal area, anal canal, and in a semen sample. Eligible men acknowledged no history of genital warts and had sexual intercourse with a woman within the past year. HPV testing by PCR and reverse line blot genotyping for 37 types was conducted on each of the specimens from the seven sampling sites. Results: When HPV results from any sampling site were considered, 237 (51.2%) men were positive for at least one oncogenic or nononcogenic HPV type, and another 66 (14.3%)