OBJECTIVE: To briefly review the effects of mindfulness on the mind, the brain, the body, and behavior. METHODS: Selective review of MEDLINE, PsycINFO, and Google Scholar databases (2003-2008) using the terms "mindfulness", "meditation", "mental health", "physical health", "quality of life", and "stress reduction." A total of 52 exemplars of empirical and theoretical work were selected for review. RESULTS: Both basic and clinical research indicate that cultivating a more mindful way of being is associated with less emotional distress, more positive states of mind, and better quality of life. In addition, mindfulness practice can influence the brain, the autonomic nervous system, stress hormones, the immune system, and health behaviors, including eating, sleeping and substance use, in salutary ways. CONCLUSION: The application of cutting-edge technology toward understanding mindfulness - an "inner technology" - is elucidating new ways in which attention, awareness, acceptance, and compassion may promote optimal health - in mind, body, relationships, and spirit.