Of the offenders, 48 percent reported no alcohol problems, 36.4 percent reported low-level alcohol problems, 8.7 percent reported intermediate-level alcohol problems, and 6.9 percent reported severe problems with alcohol. About 51 percent of offenders had no drug problems, 20.2 percent had low-level drug problems, 12.9 percent had intermediate-level drug problems, and 15.9 percent had severe drug problems. Of those who tried alcohol, 29 percent were 12 years of age or younger and 16 percent were 18 years or older. Almost 60 percent admitted to drinking alcohol regularly, at least once a week; 13 percent began drinking alcohol regularly during the preteen years and 87 percent began drinking alcohol regularly as teenagers. Of offenders who tried drugs, 65 percent did so before 18 years of age; 18 percent were preteens when they first tried drugs and 47 percent were teenagers. Further, approximately 75 percent of offenders who tried drugs before the age of 18 began using drugs regularly during their preteen years and 84 percent began using drugs regularly as teenagers. About 58 percent of the overall sample reported they had been involved in illegal activities before 18 years of age, and almost 90 percent of this group had been convicted of a crime as a young offender. A strong relationship was observed between the age at which offenders first tried alcohol and the severity of their adult alcohol problems, and similar results were obtained with regard to drug use. In general, offenders appeared to have both extensive and longstanding alcohol and drug problems. 7 references and 2 figures