Despite some success in reducing HIV incidence, the global epidemic continues to grow. For every person with AIDS in developing countries placed on treatment in 2005, many others were newly infected. We need more effective prevention programs that focus interventions on those most at risk for HIV transmission (MART), particularly those with 1) high behavioral risk and 2) high viral loads due to acute or recent infection, co-infections with other diseases, high viral set points, or untreated AIDS. This article provides examples of how prevention programs can incorporate emerging testing technologies and social/behavioral approaches to reach these individuals, their partners, and the social networks where active transmission is occurring.