Alcohol is among the most common substance to be co-administered with a variety of other drugs. It is frequently used simultaneously (i.e., on the same occasion) with cocaine. The objective of this qualitative investigation was to explore the patterns, contexts, functions, harmful consequences, risk-taking behaviors, and gender differences associated with the simultaneous use of cocaine and alcohol. In-depth semi-structured interviews with simultaneous alcohol and cocaine users were conducted at a residential treatment centre in Ontario, Canada (n=10). Two independent coders conducted a content analysis of the transcripts. Results revealed that method of cocaine use was an important variable when describing a simultaneous use occasion. There was a wide variety of reported contexts, functions, and harms associated with simultaneous alcohol and cocaine use. This research contributes to a better understanding of the patterns, functions, and contexts of simultaneous use, along with the corresponding risk taking behaviors and harms in treatment clients.