The qualitative analyses of data obtained from the interviews identified three distinct types of polydrug use among young-adult ecstasy users: the ”separate,” “synergistic,” and “indiscriminate” consumption of multiple drugs. “Separate” polydrug use refers to the use of multiple drugs as separate and unrelated experiences. Individuals in this group viewed their ecstasy use as independent from their other drug use. Those in the “synergistic” group reported numerous scenarios of polydrug use that was part of the same drug-use event. The aim of this polydrug-use pattern was to achieve the synergistic effect of the combined drugs. Individuals in the “indiscriminate” group described using multiple drugs either as independent experiences or to achieve some combined effect. In most cases, the drugs they consumed tended to be driven by their availability. The findings suggest that both “separate” and “synergistic” polydrug use tended to be intentional; whereas, “indiscriminate” use was unintentional or unplanned. The latter also tended to be associated with more risk-taking and negative outcomes, including overdosing. For this sample of young adults who had used ecstasy in the last 90 days, ecstasy tended not to be consumed on a daily basis, and it often tended not to be the drug of choice. Ecstasy was the drug of choice for only one in four of those interviewed. These findings highlight the importance of recognizing that polydrug use is a common phenomenon. The study focused on 94 ecstasy users who participated in a survey and an indepth qualitative interview between September 2002 and August 2006 in Atlanta, GA. 2 tables and 73 references