ObjectiveMindfulness‐based stress reduction (MBSR) is a structured group programme that employs insight meditation to alleviate suffering associated with physical, psychosomatic and psychiatric disorders. The programme, non‐religious and non‐esoteric, is based upon a systematic procedure to develop enhanced awareness of moment‐to‐moment experience of perceptible mental processes. The approach assumes that greater awareness will provide more veridical perception, reduce negative affect and improve vitality and coping. In the last two decades, a number of research reports have suggested support for these claims. We performed a comprehensive review and meta‐analysis of published and unpublished studies of health‐related studies related to MBSR. Materials and methods Seventy empirical studies were found, and 25 investigations met criteria of acceptable quality or relevance for inclusion in the meta‐analysis. Reports were excluded because of (1) insufficient information about interventions, (2) poor quantitative evaluation, (3) inadequate statistics, (4) mindfulness not being the central component, or (5) aspects of intervention or sample composition deviating from the health‐related MBSR programme. Acceptable studies covered a wide spectrum of clinical populations (e.g. pain, cancer, heart disease and anxiety) and stressed non‐clinical groups. Both controlled and observational investigations were included. Standardised measures of physical and mental well‐being constituted the dependent variables of the analysis. Results Overall, controlled and uncontrolled studies both showed effect sizes of about 0.5 (P < 0.05) with homogeneity of distribution. Conclusion Although derived from a relatively small number of studies, these results suggest that MBSR may help a broad range of individuals to cope with their clinical and nonclinical conditions.