Purpose/Objectives: To describe the construct of mindfulness meditation and systematically review instruments measuring the psychological impact of mindfulness-based stress reduction (MBSR) on health among patients with cancer.Data Sources: PubMed, CINAHL®, PsycINFO®, ISI Web of Knowledge®, EBSCO, and published literature (1987-2006). Data Synthesis: 13 psychological instruments used in seven studies (2000-2005) to measure effects of MBSR on health in patients with cancer were reviewed. Most studies used a one-group pre- and post-test design. The post-MBSR outcomes for each instrument varied, suggesting different yet promising relationships. For some instruments, data were insufficient to conclude sufficiently whether any were strong or appropriate to use in future intervention studies. Conclusions: To enhance knowledge of MBSR, more intervention research studies of MBSR in patients with cancer and reexamination of specific instruments are needed. Implications for Nursing: Based on the review, instruments can measure MBSR effects and found MBSR to be a potentially beneficial oncology nursing intervention.