Music is commonly associated with substance use yet little is known about the music experiences of adults with substance use disorders. In particular, there has been no detailed analysis of musical influences on emotions and cravings among clients in treatment and how these influences might occur. To explore these questions, surveys of music experiences were collected from 143 clients undergoing treatment (37 private hospital clients and 106 residential rehabilitation clients). Of the hospital sample, 70% listened to music for over an hour each day, typically while alone, and their preferred genres were pop and rock. Clients stated that music listening intensified the emotional experience of drug taking and vice versa. Residential rehabilitation clients reported that their preferred music was gloomier or heavier when using substances than when in recovery. Forty-three percent said that particular music increased their urge to use substances, and there were five common explanations, including: the song was associated with past experiences of substance use; the song evoked emotions related to substance use; and the song contained lyrics about substance use. Nevertheless, most respondents believed that music was important to their recovery. The findings are considered in terms of their clinical implications.