Assessment included a structured interview and a battery to assess social and demographic characteristics; type, frequency, and extent of substance abuse prior to incarceration; treatment history; and relation of substance use to criminal activities and life problems. Results indicate that 75 to 80 percent of those surveyed had significant life problems related to their use of alcohol and/or drugs. Legal and family problems were frequent and were highly associated with substance use in the opinions of the offenders. Despite the high prevalence of substance abuse, involvement in treatment was low, with only 55 percent of self-professed alcoholics having been involved in treatment in the last 6 months. However, 80 percent of inmates reported a need for substance abuse treatment, and individual therapy was the preferred treatment for 40 percent. Results also highlight the crime-substance use relationship: 80 percent had used drugs or alcohol on the day of the offense, and 37 percent reported having used more than usual. Finally, while many inmates had substance use-related problems, 50 to 65 percent of these had low to moderate levels of dependence, suggesting that treatment programs should incorporate both moderation and abstinence goals. 2 notes, 5 tables, and 28 references. (Author abstract modified)