Developed with the assistance of national experts on substance misuse interventions for young people, this report provides information on good practice in the field of juvenile substance misuse intervention that is consistent with national policies and existing standards and research. The service requirements for any substance misuse interventions with young people in custody are presented; the requirements allow for the interventions to be developed to meet the needs of each custodial establishment. Following a review of the policy context in which the substance misuse intervention guidelines were established, the report presents the effective practice principles for substance misuse interventions with juvenile detention populations. Ten principles of working with young people are enumerated; intervention planning should be based on these principles. The range of possible interventions with young people is presented, grouped into the five elements of: (1) identification, assessment, and planning; (2) education and prevention; (3) support and programs; (4) detoxification and clinical management; and (5) throughcare and resettlement. The wider context involving family and the community is presented next in terms of developing service with the cooperation of parents, understanding the heterogeneous nature of young offenders, and involving community-based organizations in juvenile delinquency prevention and interventions. Finally, the service requirements and essential elements of substance misuse interventions as set forth by the Youth Justice Board are enumerated, including the objective of each requirement and the success criteria against which service delivery will be measured. Tables, references