Mindfulness-based cognitive therapy (MBCT) was developed by Segal, Williams, and Teasdale (2002 Segal, Z.V., Williams, J.M.G. and Teasdale, J.D. 2002. Mindfulness-based cognitive therapy for depression: A new approach to preventing relapse, New York: The Guilford Press. [Google Scholar] ) as a therapy for relapse prevention of major depression. The 8-week group-based program combines Kabat-Zinn's (1990) Kabat-Zinn, J. 1990. Full catastrophe living: The program of the Stress Reduction Clinic at the University of Massachusetts Medical Center, New York: Delta. [Google Scholar] mindfulness-based stress reduction (MBSR) with components of Beck's (Beck, Rush, Shaw, & Emery, 1979 Beck, A.T., Rush, A.J., Shaw, B.F. and Emery, G. 1979. Cognitive therapy for depression, New York: Guilford Press. [Google Scholar] ) cognitive behavioral therapy (CBT). It is increasingly being offered by social workers worldwide. MBCT is based on an interacting cognitive subsystems model (ICS) replacing Beck's schema model. This new model represents the largest shift in the approach to major depression for social work in the past two decades. However, social work has been slow to incorporate it into its research agenda. In practice, MBCT teaches patients who are in remission from depression to become aware of, and relate differently to, their thoughts, feelings, and bodily sensations. This is a shift from CBT's schema theory that focused primarily on the content of thoughts and beliefs. A few reviews of MBCT research exist (Coelho, Canter & Ernst, 2007 Coelho, H.F., Canter, P.H. and Ernst, E. 2007. Mindfulness-based cognitive therapy: Evaluating current evidence and informing future research. Journal of Consulting and Clinical Psychology, 75(6): 1000–1005. [Google Scholar] ), but there has been no review of the mechanics of MBCT and how it addresses the cognitive patterns or metacognition and processes of major depression. There is no review of its use within the social work literature. This article discusses the mechanisms of MBCT in relation to the components of depression relapse/reoccurrence and reviews the literature regarding the effectiveness of MBCT. We found that MBCT has the potential to positively contribute to interventions directed at relapse prevention for patients with a history of depression.