Mentoring has become a popular model of intervention to reduce the risk of offending, and has been proposed as an effective tool to tackle the risk of gang membership. This paper reviews the existing literature on mentoring and reports on a qualitative evaluation of a mentoring programme targeted at young people "at risk" of gang membership in an English city. The study highlights important issues around these interventions. Although we found it a useful way to engage otherwise hard-to-reach families, important limitations remain: their potential labelling impact and their limited impact in isolation from other more ambitious measures.