Syphilis is a multistage infectious disease that is usually transmitted through contact with active lesions of a sexual partner or from an infected pregnant woman to her fetus. Despite elimination efforts, syphilis remains endemic in many developing countries and has reemerged in several developed countries, including China, where a widespread epidemic recently occurred. In the absence of a vaccine, syphilis control is largely dependent upon identification of infected individuals and treatment of these individuals and their contacts with antibiotics. Although penicillin is still effective, clinically significant resistance to macrolides, a second-line alternative to penicillin, has emerged. Macrolide-resistant strains of Treponema pallidum are now prevalent in several developed countries. An understanding of the genetic basis of T. pallidum antibiotic resistance is essential to enable molecular surveillance. This review discusses the genetic basis of T. pallidum macrolide resistance and the potential of this spirochete to develop additional antibiotic resistance that could seriously compromise syphilis treatment and control.Spirochetes are motile, spiral-shaped bacteria that are divided into the families Spirochaetaceae, Brachyspiraceae, and Leptospiraceae (54). Treponema species, which are members of the family Spirochaetaceae, are fastidious anaerobic or microaerophilic host-associated spirochetes. While the majority of Treponema species are found in the flora of humans and animals, a few species are pathogenic for humans. Treponema pallidum subspp. pallidum, endemicum, and pertenue,