Sleep disturbance is a very common problem for cancer patients that has largely not been addressed in the clinical intervention literature. Mindfulness meditation has demonstrated clinical benefits for a variety of patient populations in other areas of functioning. This study examined the effects of an 8-week Mindfulness-Based Stress Reduction (MBSR) program on the sleep quality of a heterogeneous sample of 63 cancer patients. Overall sleep disturbance was significantly reduced (p < .001) and participants reported that their sleep quality had improved (p < .001). There was also a significant reduction in stress (p < .001), mood disturbance (p = .001), and fatigue (p < .001). The associations among these changes and implications for improving quality of life of cancer patients are discussed.