Implementation of effective substance abuse treatment programs in community settings is a high priority. The selection of a proven cost-effective model is a first step; however, difficulty arises when the model is imported into a community setting. The Center on Substance Abuse Treatment selected a brief substance abuse treatment program for adolescents, the MET/CBT-5 program, determined to be the most cost-effective protocol in the Cannabis Youth Treatment trial, for implementation in two cohorts of Effective Adolescent Treatment grantees. A qualitative investigation of the protocol implementation with nine sites in the second cohort chronicled adaptations made by grantees and prospects for sustainability. The study found that agencies introduced adaptations without seeming to be aware of potential effects on validity. In most sites, sessions were lengthened or added to accommodate individual client needs, address barriers to client participation, and provide consistency with current norms of treatment. Implications for fidelity of future implementation projects are addressed.