Developments in Ireland over the last two decades have led to a questioning of, and challenge to, traditional methods of treatment offered by addiction counsellors (McCann, 2002).With this in mind, the present study examines whether participation in a client-centered treatment (n=60) was associated with positive outcomes, and how outcomes of this approach compared with those of a cognitive behaviour treatment in an all-male prison sample (n=55). Participants in the client-centered treatment comprised 60 members of the Traveller community of mixed age and gender. Based on an analysis of client files, a between subjects design was used to compare the effectiveness of treatment outcome, using measures of abstinence, reduction, maintenance and relapse. Statistical analysis reveals a significant difference in treatment outcome, however positive results are mitigated by small sample size and lack of between-group comparisons in this study, therefore conclusions about the comparative effectiveness of treatments must be interpreted with caution. This circumscribed conclusion leaves open the possibility that other comparative studies, using different measures, or longer follow-up, could reach different conclusions.