Data from the Drug Use Forecasting program indicate that more than half of arrestees test positive for drugs. People use illegal drugs for many of the same reasons they turn to beverage alcohol. Addiction is not an invariable outcome of drug or alcohol use; the effects differ in different people. Major types of drugs are depressants such as heroin and barbiturates, stimulants such as cocaine and amphetamines, and hallucinogens such as marijuana and LSD. Drug abusers are reluctant to admit that they have the problem and will tend to try to hide it while under correctional supervision if they have not admitted it during the initial interview. Identification and assessment of offenders in trouble with illegal drugs is a crucial component of correctional work. Correctional workers should try to identify drug problems during the initial contacts by checking records or noticing behaviors that suggest drug problems. They also need to know that drug testing technology has made great advances in recent years. Therapeutic communities are considered to be the most successful drug rehabilitation programs. The many nonresidential support options include Narcotics Anonymous and Cocaine Anonymous. Some carefully screened addicts can avail themselves of medication to assist in their treatment. Correctional workers will probably not be directly involved in treatment, but they will be indirectly involved by being knowledgeable about local programs, insisting on drug testing, and holding offenders responsible for remaining alcohol- and drug-free. Table, case study, and 33 references