This article presents the results of an evaluation of Orientation and Serological Support Centers, or Anonymous HIV Testing Centers, in the Northeast of Brazil. Methodological triangulation was used to evaluate these health programs and services, including qualitative and quantitative methodology and pointing to the insufficiency of single-discipline reasoning to encompass phenomena in social organizations. The article also shows results from this triangulation experience, seeking to combine Social Sciences and Epidemiology. It describes the structure and dynamics of these services, analyzes the relationships, perceptions, and representations of the actors, presents a self-evaluation by the professionals, expounds on some quantitative results, and discusses some limits and problems, as well as proposals to overcome them.