Mindfulness-based stress reduction is efficacious in reducing mental health symptoms among cancer patients; however, there is a paucity of research of protective concepts such as spiritual well-being and hope and whether such concepts can be cultivated through MBSR among this population. In this trial, we examined the efficacy of a MBSR program in increasing spiritual well-being and hope among patients with breast cancer. This is a two-arm, waitlist randomized controlled trial with pre-and postassessments. This article follows Consolidated Standards of Reporting Trials guidelines. Sixtythree patients with breast cancer were recruited and randomly assigned to the intervention (n = 31) or a waitlist control conditions (n = 32). Patients in the intervention condition received a modified MBSR program. All patients in the trial completed measures of spiritual well-being Scale and Snyder Hope Scale pre-and posttreatment. To evaluate trial hypotheses, we conducted per protocol repeatedmeasures analyses of variances. Patients with breast cancer in the MBSR group reported significant increases from pre-post treatment in total spiritual well-being and hope scores compared to patients in the waitlist control condition. These results suggest MBSR may improve spiritual well-being and hope in patients living with breast cancer. As patients in the current trial were of the Muslim faith, the generalizability of the findings may be limited. Future research needs to include larger samples and patients from different religions to replicate findings. The study emphasizes that MBSR can be considered in oncology care programs by health care professionals, in educational curriculums, and suggested for use among caregivers and breast cancer patients.