IntroductionMindfulness-based treatments have received increasing interest and empirical support in the clinical psychology literature. There are, however, no studies to date that have systematically examined treatment enactment, which is the amount and type of home practice participants incorporate into their daily lives. Because treatment enactment has been cited as a key aspect of treatment fidelity, this study examined the relationships between treatment enactment (i.e., home mindfulness practice) and alcohol and other drug (AOD) use and craving in the context of a larger study of mindfulness-based relapse prevention (MBRP). Methods Participants (N = 93) in this secondary analysis had been randomized in the parent study to receive MBRP. AOD use, craving, and home mindfulness practice were assessed at baseline, post-treatment, 2-month and 4-month follow-up time points. Results MBRP participants significantly increased the amount of time spent in home mindfulness practice over the course of the study. Further, greater time spent in home practice was associated with less AOD use and craving at the 2- and 4-month follow-ups. Of note, the significant treatment gains in home practice faded somewhat at the 2- and 4-month follow-ups as participants returned to standard aftercare, which did not involve mindfulness-based practice. Conclusions Participation in MBRP was associated with a significant increase in home mindfulness practice, and increased involvement in home practice was associated with significantly lower AOD use and craving over the course of the study. This suggests that treatment enactment, which entails building mindfulness practice into one's daily life, plays a key role in ongoing recovery following MBRP treatment. Teaching mindfulness skills for daily use versus for only in high-risk situations has the potential to boost the longevity of MBRP treatment effects. These findings also suggest that MBRP clinicians should target the post-intervention decline in home practice (e.g., with ongoing mindfulness practice groups) to maximize the benefits of mindfulness meditation in decreasing AOD use and craving.