Background * The challenge to determining the true impact of HIV within the general population in China has been the lack of a reliable, comprehensive surveillance and reporting system, coupled with the lack of an effective referral chain within the Chinese healthcare system. However, over the past few years, more information has become available about specific, at-risk populations. * The nature of China’s HIV epidemic complicates assessments about its future. The vast majority of Chinese persons harboring HIV are within marginalized, at-risk, and hard-to-reach populations, such as intravenous drug users (IDUs), commercial sex workers (CSWs), and increasingly within the migrant labor population. Moreover, the disease is found predominantly in more remote and poor areas of China, and it disproportionately affects ethnic minorities, especially in southwestern and western China.