The CSAT Methamphetamine Treatment Project (MTP) is a multisite study with a two-fold purpose: to assess the feasibility and outcomes generated by a technology transfer of the Matrix treatment model for methamphetamine (MA) abuse into several community-based treatment programs, and specifically to compare outcomes of treatment as usual at each site with outcomes of the Matrix model, as implemented in each site. The study comprises seven sites, geographically situated in Hawaii, Northern and Southern California, and Montana. This article presents a demographic description of the cohort, and describes patterns of drug use, abuse, and related problems among the 169 participants recruited in the first six months of the study, from April through September 1999. Specific analyses presented include: demographic composition of the sample with respect to gender, age, ethnicity, education completed, employment status, and income; primary drug used, and mean percent of days using various drugs including MA, alcohol, and marijuana; and percent of sample reporting various routes of drug administration. Mean baseline Addiction Severity Index composite scores are presented that describe medical, employment, alcohol, drug, legal, family/social, and psychiatric status for the sample. Also presented here are comparisons of this preliminary population to other populations reported in the literature. This early subset of MTP participants is similar to other methamphetamine-abusing populations described in the literature in age, years of education, income, and mean years of use. However, because of its multisite structure and the locations of its constituent sites, the MTP population has greater variation in ethnic makeup than do populations from other studies, offering an opportunity to provide useful new information about drug use patterns and treatment responses in populations not previously studied.