There is a lot of research on adolescent alcohol and other drug (AOD) treatment. But little research has been published on adolescent AOD treatment in general and much less has been reported on the gender and ethnic differences in referral/admission and treatment discharge information. This exploratory study examined the characteristics of adolescents entering all publicly funded AOD treatment in a San Diego (California) county from 1997 to 1999. The results show that males were more likely than females to enter treatment. Alcohol and marijuana were found to be frequently reported substances used by the youth in this sample. Two thirds of the youth reported two problem substances, reflecting the national finding that poly substance use among adolescents is related to higher treatment utilization. There were a number of differences between the males and females entering and exiting treatment. The males were found to enter treatment through the criminal justice system, use marijuana and alcohol, and were more likely to be mandated to treatment compared to the females. Methamphetamine use was reported by more than one quarter of the treatment population. This form of stimulant use was most prevalent among females and White adolescents, with a fairly high percentage of these users reporting injection drug use. The study reflected ethnic differences in both treatment outcome and referral source, with African-American and Hispanic youth being overrepresented in the group of youth referred by the criminal justice system and group mandated to attend treatment. Non-White adolescents were more likely than their White counterparts to have unsuccessful treatment outcomes. Such unsuccessful outcomes are in contrast to White adolescents that might be classified as having more severe AOD problems. Possible areas for future research include examination of the cultural sensitivity and appropriateness of treatment, how ethnicity is related to drug use patterns, and the influence of socioeconomic factors. The examination of oppression and racism as they might relate to the adjudication of non-White youths to AOD treatment is also suggested. 6 tables, 35 references