The National Human Immunodeficiency Virus (HIV) Behavioral Surveillance System (NHBS) is the Centers for Disease Control and Prevention's (CDC's) newest system for measuring HIV risk behaviors among three adult populations at highest risk for HIV infection in the U.S.: men who have sex with men, injecting drug users, and heterosexuals at risk of HIV infection. The system is implemented by state and local health departments in designated metropolitan statistical areas with the highest HIV/acquired immunodeficiency syndrome (AIDS) prevalence in the U.S. Prior to implementing the behavioral surveillance survey, project sites conduct a series of formative research activities. The data collected during this preparatory phase provide contextual information about HIV risk behaviors within the study population of interest and help project sites make decisions about field operations and other logistical issues. This article describes the activities undertaken in preparation for the first round of NHBS (2003-2007) and how those activities enhanced data collection for each behavioral surveillance cycle.