Although punishment still dominates the criminal justice system, the progression of research on offending and imprisonment has led to a general consensus that rehabilitation programmes are the appropriate method to effectively reduce both recidivism and prison populations. Hence, many effective offender treatment programmes have been developed. This thesis evaluated phase one of a 10 month pilot treatment programme which used the theories and principles of effective programming to develop an effective programme for male high risk violent offenders assessed with elevated psychopathic personality (High Risk Personality Programme; HRPP), a population of offenders that is often regarded as treatment resistant. Specifically, phase one of the HRPP was designed to address the participants’ responsivity barriers (namely, antisocial interpersonal style) in order to increase self-efficacy, therapeutic alliance, treatability, and readiness, and to reduce perceived coercion in order to aid engagement and success in treatment. A sample of 11 male HRPP inmates had data collected before and after their 17-week first phase of the 10 month three-phase programme. Treatment contact comprised four sessions per week, including three group sessions of 2.5 hours, and 1 individual session of one hour, as well as a two-hour group cultural session that focused on Maori cultural identity (10 of the 11 men were Maori). The battery of tests employed included the Self-Efficacy Questionnaire; the responsivity and readiness scales of the Treatment Readiness Responsivity and Gain Scale; the Corrections Victoria Treatment Readiness Questionnaire, the Paulhus Deception Scale, and the therapist and client versions of the Working Alliance Inventory Short Form, the Perceived Coercion Scale, and an evaluation questionnaire. Demographic data was also collected. The results indicated that the majority of the participants came to the intervention ready or motivated to change. Perceived coercion remained low throughout the programme, representing the participant’s voluntary status. On average participants’ levels of self-efficacy and treatability (except callousness) improved significantly over the course of the treatment. Differing levels of improvement were found for the client and therapist perspective of the therapeutic alliance, indicating they interpreted the alliance differently. Participants with high PCL-R factor one scores showed a decrease in coercion, compared to an increase by their counterparts with low PCL-R factor one scores. Participants with high PCL-R factor one scores also had higher overall scores on the CVTRQ readiness measure, and the participant’s perspective of the therapeutic alliance. Individually, six of the treatment participants made significant improvements on at least five of the seven responsivity measures. These findings and their implications for treatment of psychopathic offenders are discussed, along with the relevance of the study’s responsivity measures, the strengths and limitations of the research project, and future research in this area.