This paper provides a comprehensive overview of the relevant existing evidence, and critically appraises the use of mindfulness-based stress reduction (MBSR) in cancer care. Furthermore, a meta-analysis was conducted in order to investigate the effect of MBSR on quality of life (QoL), mood, and distress. Besides 6 reviews (5 systematic, 1 meta-analytic) which are reported separately, a total of 19 original research papers fully met the inclusion criteria for the systematic review. The 19 original papers consisted of 5 randomised controlled trials (RCTs), 4 non-randomised controlled trials (NRCTs), 9 observational studies (OS) and 1 two-arm observational study. The included outcome measures were QoL, mood, and distress. Cohen’s effect size d was computed for each category. Estimating the effect on QoL, a total of n = 248 patients out of 6 studies was included and the overall effect size was 0.29 (95% confidence interval (CI) 0.17–0.40; p ≤ 0.00005). Calculating the effect on mood, a total of n = 411 patients out of ten studies were included, and the overall effect size was 0.42 (95% CI 0.26–0.58; p < 0.0001). Reduction in distress revealed an overall effect size of 0.58 (95% CI 0.45–0.72; p < 0.0001; n = 587 patients out of 15 studies). MBSR programmes can improve QoL and mood, and reduce distress in cancer patients. However, there is an urgent need for more high quality RCTs implementing adequate controls, longer follow-up periods, sufficient samples sizes, clear descriptions of patients’ psychological profiles, and the accompanying utilisation of qualitative measures.