The Methamphetamine Treatment Program (MTP), funded by the Center for Substance Abuse Treatment, has the objectives of implementing the Matrix outpatient model and evaluating that model in comparison to the existing community "treatments as usual." Seven organizations in three western states (California, Montana, and Hawaii) were selected to participate in this randomized, controlled, multisite project in what constitutes the largest trial to date of treatment for methamphetamine (MA) dependence. One hundred fifty MA-dependent patients recruited at each site are randomly assigned to receive either the Matrix model, a manualized program of intensive outpatient treatment, or the site's standard treatment, "treatment as usual." Participants are evaluated at admission, weekly during treatment, at the time of scheduled discharge, and at six and 12 months after admission. Dependent measures assess changes in drug use, HIV risk behaviors, quality of life, and patient satisfaction. Cost analyses to quantify treatment costs and determine the association between costs and clinical outcomes will be conducted. A number of adjustments in the original study design have been necessitated by the realities of community sites' strengths and limitations. Experiences from this multisite project will also provide a model for other efforts to transfer research-based treatments into community settings. This article describes the main aims of the project, the background and rationale for the study design, a brief description of the research plan, and methods implemented to protect the integrity of the science.