Implementation of evidence into practice is a complex and multi-dimensional process. There has been rapid expansion in published theoretical and empirical literature on Mindfulness-Based Stress Reduction (MBSR) and Mindfulness-Based Cognitive Therapy (MBCT). However, there has been little research or theoretical analysis of the processes involved in translating the new evidence into practice. Within the thesis aspects of the MBSR/MBCT implementation process are analysed and researched, with a particular focus on training practitioners, development and assessment of teaching competence, and the barriers and facilitators to implementation in health care settings. The thesis includes six peer reviewed scientific journal papers – two theoretical papers on training and on competence; an empirical paper presenting the development of a system for assessing mindfulness-based teaching competence (the Mindfulness-Based Interventions: Teaching Assessment Criteria) and the initial validation of this tool; research using Conversation Analysis methods on interaction between teacher and participants in mindfulness-based courses; a survey based analysis of the implementation of MBCT within the UK health service; and finally a personal reflective process on the themes that are addressed within the thesis. The critical analysis which brings the papers together as a thesis includes an overall introduction to the context for the investigations; an introduction to and analysis of the original contribution of each paper; and a final concluding section which takes a meta-perspective on the issues and themes that are investigated within the thesis. The overall key contributions which emerge from this body of work include an analysis of the implications of the theories underpinning mindfulness-based approaches for MBSR/MBCT teacher training programmes; the introduction into the field of a new way of articulating the distinctive features of mindfulness-based competence, based on a synthesis of theories on competence in related fields with those on mechanisms underpinning mindfulness; identification of the key features of MBSR and MBCT teaching competence and the translation of these into a validated tool for assessing mindfulness-based competence; and finally platform research on the barriers and facilitators to MBCT implementation within the UK health service.