Past research findings indicate that drug use and mental health problems among adolescents from rural areas of the United States have equaled or exceeded those of nonrural youth. However, these research findings were limited in their use of community samples. This study attempted to bridge the research gap and examined differences between juvenile-justice-involved rural and nonrural adolescents enrolled in drug treatment for substance abuse and mental health problems (a) at treatment entry and (b) at 3, 6, 12, and 30 months following treatment. Five hundred and twenty-three adolescents participated in the study and entered 1 of 3 geographically diverse substance abuse treatment programs between 1997 and 2001. Results from this study include: (1) a replication of previous findings regarding a smaller percentage of females enrolled in substance abuse treatment; (2) lower mean scores for rural youth were found regarding overall frequency of use as well as problems associated with use; (3) African-American rural youth reported less use and problems with use than did other groups; (4) both general mental health and depression were less severe for rural youth enrolled in substance abuse treatment; and (5) there were more similarities than differences in substance use change trajectories of rural and nonrural youth. In summary, the outcome findings support the overall positive effects of treatment with regard to both substance use and mental health, and rural and show that nonrural adolescents are more similar than had been expected. Tables, figures and references