Portal surveys, defined as assessments occurring proximal to the entry point to a high-risk locale and immediately on exit, can be used in different settings to measure characteristics and behavior of attendees at an event of interest. This methodology has been developed to assess alcohol and other drug (AOD) use at specific events and has included measuring intentions to use collected at entry and reported use on exit, as well as chemical tests for AOD consumption at both entrance and exit. Recent applications of the portal survey procedure to electronic music dance events that occur in established venues (e.g., bars or nightclubs) are discussed.