OBJECTIVES: This study aimed to identify demographic, psychological, health-related, and geographic predictors of adherence to home-based and supervised components of a yoga intervention in breast cancer survivors. METHODS: Participants were the 32 post-treatment breast cancer survivors who were randomized to the Viniyoga intervention arm of a controlled trial. Participants were asked to practice yoga 5 times per week for 6 months, including at least one weekly facility-based session. Adherence was monitored using sign-in sheets and logs. Height and weight were measured; other potential predictors of adherence were obtained from baseline questionnaires. RESULTS: Participants attended 19.6+/-13.0 yoga classes and performed 55.8+/-32.8 home-based yoga sessions. Participants adhered to 58% of the overall yoga practice goal (75% of the goal for yoga classes and 54% of the goal for home based-sessions). Higher class attendance and home practice were predicted by greater self-efficacy for yoga (p=0.004 and 0.06, respectively). Additionally, employment outside the home was associated with greater class attendance (p=0.004), while higher waist circumference was marginally associated with lower adherence to home-based yoga (p=0.05). CONCLUSIONS: High levels of facility- and home-based yoga practice were achieved. Breast cancer survivors who have lower self-efficacy for yoga or who have a higher waist circumference may benefit from additional support or intervention tailoring. Adherence may also be improved by ensuring that class times are convenient to both working and nonworking women.