Data were collected in the spring of 1986 using self-administered questionnaires. Analyses were performed separately for each racial subgroup. Simple correlations revealed that self-reported alcohol, tobacco, marijuana, and other illegal drug use were all significantly related to both minor and violent delinquency for all three racial groups. Multiple regression analysis revealed that the use of these substances accounted for 40 percent to 47 percent of the variance in minor delinquency and for 59 percent of the variance in violent delinquency among blacks, 53 percent of variance in violent delinquency among Mexican-Americans, and 34 percent of the variance in violent delinquency among whites. The best predictors of violent delinquency were the frequent use of illegal drugs other than marijuana and use of tobacco, in that order, among Mexican-Americans; the frequent use of other illegal drugs, marijuana, and tobacco, in that order, for whites; and the frequent use of illegal drugs, followed by marijuana, for blacks. 3 tables, 12 references. (Publisher abstract)