OBJECTIVE: To conduct a pilot trial of internet-based, cancer-adapted yoga for women receiving breast cancer treatment.DESIGN: Women undergoing radiation or chemotherapy for breast cancer were recruited for 12, 75-min, biweekly, cancer-adapted yoga classes delivered via internet-based, multipoint videoconferencing. Data were collected on feasibility and acceptability, including qualitative feedback from participants and the yoga instructor. RESULTS: Among 42 women approached, 13 declined eligibility screening, and 23 were ineligible. All 6 women who were eligible provided consent, but 2 withdrew prior to beginning yoga classes. The remaining 4 participants attended 1-11 of 12 online yoga classes. In post-intervention interviews, participants and the instructor agreed that internet-based yoga classes hold great potential for increasing access and improving psychological outcomes in adults with cancer. Qualitative feedback from participants revealed suggestions for future trials of internet-based, cancer-adapted yoga classes, including: continued use of group format; offering more varied class times to accommodate patients' demanding schedules and fluctuating symptoms; enrolling patients after they have acclimated to or completed cancer treatment; streamlining the technology interface; and careful attention to participant burden when designing surveys/forms. The instructor recommended closed session courses, as opposed to rolling enrollment; teaching the same modified poses for all participants, rather than individual tailoring; and using a large screen to allow closer monitoring of students' class experience. CONCLUSIONS: Internet delivery may increase patients' access to cancer-adapted yoga classes, but cancer-related and technological barriers remain. This study informs how to optimally design yoga classes, technology, and research procedures to maximize feasibility and acceptability in future trials.