A comprehensive assessment of an individual's drug problem needs to include consideration of the type, frequency and amount of drug use, degree of dependence, concomitant medical problems and general health, previous treatment history, family and social relationships, employment and financial situation, psychological functioning, criminal activity and legal situation. The aim of a community based drug advisory service in Sydney is to provide an assessment-referraltreatment service which aims to match an individual's drug-related problems to the most appropriate range of therapeutic interventions. The components of the system include: intake, assessment, case conference, intervention and research. The system also accommodates the NSW Drug and Alcohol Court Assessment Program which interfaces Criminal Justice and Health Systems. Clinical programs of the service are described including a methadone maintenance program.