Syphilis rates in women and congenital syphilis rates have declined steadily in the United States in recent years. However, syphilis remains a worldwide public health problem, with more than 12 million cases in adults and more than half a million pregnancies affected yearly. Prenatal screening and treatment programs are limited or nonexistent in many developing countries. The genome of Treponema pallidum, one of the smallest among prokaryotes, has been sequenced, but methods for continuous in vitro cultivation of the microbe remain elusive. There are no promising candidates for future vaccines at this time. Serologic testing, for both specific treponemal and nontreponemal antibodies, continues to be a primary means of diagnosis. Penicillin remains the drug of choice for congenital and acquired syphilis in childhood. The diagnosis of syphilis beyond early infancy raises concerns for possible child sexual abuse, although progression of congenital syphilis may account for some cases. Syphilis is a potentially eradicable disease, but this can be achieved only with sustained international will and cooperation to fund the necessary screening and treatment programs.