After a precipitous increase in the incidence of infectious syphilis in the United States during the late 1980s and early 1990s, the rate of new cases has declined so dramatically that a program initiated by the Centers for Disease Control and Prevention (CDC) to achieve elimination appears to stand a good chance of succeeding. In the fall of 2000, the CDC convened an advisory group to examine the recent medical literature regarding syphilis treatment. Published literature in peer-reviewed journals and abstracts from relevant scientific meetings that have appeared since the last STD Treatment Guidelines meeting in 1997 were reviewed. Where applicable, unpublished data from studies in progress were also discussed. Expert opinion was sought. Through all these efforts, it appears that the azalide azithromycin and the third-generation cephalosporin ceftriaxone should find more definitive roles in the treatment of syphilis. None will eclipse the continued primacy of penicillin for this purpose.