The most common DSM-IV substance use disorder diagnosed in the American-Indian adolescent sample was marijuana dependence (51.7 percent), followed by alcohol abuse (33.7 percent), alcohol dependence (33.7 percent), and marijuana abuse (32.6 percent). Among those reporting alcohol, marijuana, and stimulant use, the most frequently endorsed abuse criterion was Impaired Role Obligations, while the two most frequently endorsed dependence criteria were Use Despite Substance-Related Psychological/Physical Problems and Unsuccessful Attempts to Quit/Cut Down. The findings suggest that the drug problems of American-Indian adolescents admitted to residential substance abuse treatment are serious and complex and present a significant challenge to the substance abuse treatment community. Participants were 89 American-Indian adolescents recruited from a Residential Substance Abuse Treatment Program (RSATP) for male and female American-Indian adolescents. Participants were administered the Composite International Diagnostic Interview-Substance Abuse Module, which measures significant drug and alcohol use and is capable of generating past-year DSM-IV diagnoses. Data were analyzed using SPSS for Windows and involved the calculation of Spearman Rank Correlations. Future research should attempt to replicate these findings with larger samples. Tables, references