A comprehensive interviewer administered a questionnaire, and other measures such as content analysis of medical and criminal records provided the data base. To enable a thorough analysis, and a comparison across record types, an 8-point classification system was used. This system incorporated dimensions of 'consumption,' 'dependency,' 'association with crime,' and 'self perception: for alcohol and drug use. The results suggest that one-third of the sample consume 'hazardous' amounts of alcohol. Only 6 percent of the sample were classified as current drug dependents. The results support previous research which indicates that alcohol abuse amongst offenders is a major problem. The groups that emerge as the main concerns are: Aboriginal alcohol abusers, alcohol abusers not concerned with their alcohol use, drunk drivers, and women drug and alcohol abusers. The validity of the screening instruments is examined, a strategy for screening for drug and alcohol problems is suggested, and the implications of the results for prevention and treatment interventions is discussed. (Author abstract)