Border areas are important locations for understanding HIV transmission. This study examines individual and network correlates of border crossing and equipment sharing among methadone maintenance clients in Ruili City, a Chinese city on the Myanmar border. Data are from 298 clients enrolled in the Ruili Methadone Treatment Center. Clients were interviewed about drug use, HIV/AIDS knowledge, treatment motivation, and their social networks. Multinomial and logistic regression analysis were performed. Thirty percent of clients reported injecting in Myanmar. Compared to drug networks that usually inject in China, networks that inject equally in both places (border crossing) are more likely to share equipment. The association between HIV positive status and border-crossing was marginally significant and robust. Results indicate some added degree of risk among clients and drug networks who border-cross to use drugs. More research is needed to understand this phenomenon.