Seven sites in three western states (California, Montana, and Hawaii) have been selected to participate in the randomized, controlled, multisite project in what constitutes the largest trial to date of treatment for methamphetamine (MA) dependence. Study participants include 150 MA-dependent patients recruited at each site who have been randomly assigned to receive either the Matrix model, a program of intensive outpatient treatment, or the site's standard treatment. Participants are to be evaluated at admission, weekly during treatment, at the time of scheduled discharge, and at 6 and 12 months after admission. Dependent measures will assess changes in drug use, HIV risk behaviors, quality of life, and patient satisfaction. Cost analysis will quantify treatment costs and determine the association between costs and clinical outcomes. Several adjustments in the original study design have been necessitated by the realities of strengths and limitations of the community sites. Experiences from the multisite study will provide a model for other efforts to transfer research-based treatments into community settings. The end result will be a rigorous and scientific comparison of the Matrix approach and existing community treatments. The article describes the main aims of the project, the background and rationale for the study design, and a brief description of the research plan. 14 references and 2 tables