Over the years, behavioral surveillance surveys (BSS) have been shown to make an important and useful contribution to informing the national response to HIV. These surveys use reliable methods to track HIV risk behaviors over time as part of an integrated surveillance system which monitors various aspects of the epidemic. In response to the growing interest and experience in BSS, this document presents guidelines for repeated behavioral surveys in populations at risk of HIV. It provides a "one-stop" reference to help public health officials set up and manage systems that provide reliable trends in HIV risk behaviors. Information is also provided to help those who will be implementing the surveys themselves. Divided into nine major chapters, the areas covered include: importance of behavioral surveillance, setting up BSS, choosing populations for behavioral surveillance, sampling, analysis issues related to multi-stage cluster sampling, selecting and adapting questionnaires, data analysis, data use, and indicators. The annexes provided at the end of the document include other useful items such as standardized questionnaires, fieldwork forms, examples of interviewer guidelines, and detailed descriptions of the sampling process.