Sexually transmitted infection (STI) patients co-infected with syphilis and HIV have some of the highest HIV transmission probabilities, yet many STI patients often never receive screening for either of these frequently asymptomatic STIs. This KOI application details a four year plan focused on implementing integrated syphilis/HIV services in South China, a region characterized by hyper endemic syphilis transmission and increasing sexual HIV transmission. Linking clinical epidemiology and social science methods, the research and training plan will be mentored by Dr. Myron S. Cohen (Infectious Diseases), Dr. Xiang-Sheng Chen (Epidemiology), and Dr. Martin K. Whyte (Sociology). The training component will include advanced coursework on clinical epidemiology, anthropology, and Mandarin Chinese to complete a Masters in Regional Studies East Asia (MRSEA) at Harvard. As an Infectious Disease Fellow at the Massachusetts General Hospital, I completed a preliminary study that found HIV to be independently associated with syphilis infection at STI clinics in South China. Syphilis test acceptance at STI clinics was greater than 90%, but HIV testing acceptance was poor. Responding to South China's expanding syphilis epidemic, the WHO has launched a pilot program in two cities providing free rapid syphilis testing at select STI clinics, introducing a special opportunity for parallel HIV operational research. Transitioning to the Massachusetts General Hospital faculty with my mentor's support, I will focus on the following three specific aims: 1) To analyze STI patient characteristics that correlate to accepting HIV testing at STI clinics; 2) To describe the social and cultural context of HIV testing STI patients using qualitative methods; 3) To assess STI physician characteristics that correlate to offering HIV testing. The proposed training and research program will provide a foundation to understand the complex biosocial fabric of rapidly evolving sexual health behaviors in China, uniquely positioning me as a junior investigator to implement novel behavioral responses to the twin epidemics of syphilis and HIV in China.