New tools have made it possible to identify clusters of ongoing HIV transmission through the analysis of HIV molecular data. Although analysis of molecular data to understand transmission clusters has become more widespread in recent years, such analysis has typically been retrospective. Now, public health agencies are beginning to use data routinely collected through surveillance to prospectively identify clusters for public health response aimed at strengthening prevention efforts and ensuring that people with and at risk for HIV have access to the services they need. Cluster detection efforts can be used to prompt public health action, but this work must be done in a way that maximizes benefit and minimizes potential harms. This presentation will describe this new strategy and the promise it holds for HIV prevention.