The purpose of this study was to investigate the effectiveness of the mindfulness-based cognitive therapy-assessment scale (MBCT-AS) tool to measure treatment fidelity in the delivery of mindfulness-based cognitive therapy (MBCT) in an Australian setting. The work was set as part of Depression Awareness Recovery Effectiveness (DARE) program, which was a large pragmatic randomised controlled trial (RCT) using MBCT. Qualitative and quantitative data was sourced through analysing randomly selected video recordings of the program sessions delivered by Australian MBCT trainers. Twenty-two randomly selected sessions were coded and analysed to evaluate trainer fidelity (TF) to the established treatment model. The aim of the study was to detail an analysis of the treatment model, the provision of strategies for future decision-making, and the implementation of therapeutic techniques. Patterns emerged from the data that provided a foundation for analysis and clarification of the integrated model in terms of TF. The results of this study were organised into four research categories: fidelity to the integrated model compared to original founder findings, effects of gender difference on fidelity, MBCT implementation experience levels affecting fidelity, and effect of TF on the outcome measures of patients. Results indicated that therapists' maintained high treatment fidelity to the MBCT model. Clinical implications and limitations are highlighted.