Multisystemic Therapy has begun to be disseminated in New Zealand and represent one of the preferred approaches of a recent national interagency plan for severe conduct disorder and antisocial behaviour. Findings from a recent meta-analysis have suggested that dissemination of Multisystemic Therapy may be subject to setting effects (Curtis, Ronan, & Borduin, 2004). This study reflected features previously associated with lower effect sizes. Therefore, one aim of this effectiveness study was to compare findings from the initial dissemination of MST in community mental health settings in New Zealand with findings from US-based randomized controlled trials. Sixty five antisocial youth, along with their families, participated in the study across three different settings. Findings demonstrated significant pre- to post-treatment improvements in most indicators of ultimate (i.e., offending behavior) and instrumental (i.e., youth compliance, family relations) treatment outcomes. Reductions in offending variables continued to improve across follow-up intervals. Further, successful treatment completion rates in this study (98%) were significantly greater compared to the average completion rate found in previous MST studies. Additional benchmarking indicated that effect sizes compared favourably with those seen in previous MST research focused on juvenile offenders. Families generally reported high levels of satisfaction with the program. Most also felt that it met youth and family cultural needs. Issues related to continuing dissemination of MST, including an expanded role for benchmarking, are discussed.