This project report is about welfare policy responses to crime committed in youth gangs. In a literature review we were concerned with the phenomenon of juvenile delinquency and respective prevention measures to reduce the number of young people who join youth gangs. After a review on youth gang research and a discussion on positive changes in the life cycle, three kinds of interventions are presented as examples for social responses to the problem of youth gangs: 'Police counselling in schools', 'positive role models in communities', and 'social network and family conferences'. The final section of this report discusses management approaches and pitfalls in multi-agency policing in regard to successful implementation of crime prevention partnerships.