The Harvard University Asia Center hosted a symposium in October 2010 focused on sex work and sexually transmitted infections in Asia, engaging a biosocial approach to promote sexual health in this region. Asia has an estimated 151 million cases of curable sexually transmitted infections (STIs; eg, syphilis, gonorrhea, chlamydia) each year, with commercial sex interactions playing a large role in ongoing transmission. Substantial human movement and migration, gender inequalities, and incipient medical and legal systems in many states stymie effective STI control in Asia. The articles in this supplement provide theoretical and empirical pathways to improving the sexual health of those who sell and purchase commercial sex in Asia. The unintended health consequences of various forms of regulating commercial sex are also reviewed, emphasizing the need to carefully consider the medical and public health consequences of new and existing policies and laws.