Given that the development of treatment fidelity assessment protocol is an integral but too frequently ignored aspect of clinical trials for psychological treatments, the Intensive Mental Health Program (IMHP) sought to build fidelity activities into training, program evaluation, and clinical recordkeeping from the outset of a 3 year study period. We describe (a) operational definitions and measurement of the IMHP treatment model, (b) planned fidelity-promoting activities, (c) evaluation methods, and (d) fair to appreciable accomplishment of IMHP fidelity targets. Discussion of the circumstances and processes possibly hindering better fidelity for several IMHP treatment features accompanies presentation of fidelity data. We summarize pitfalls and compensatory strategies identified during IMHP program evaluation and offer practical suggestions to enhance accountability and evaluative activity in future clinical research.