This paper aims to explain the concentrated offending behaviour of children in residential care. The author considers whether children's residential care is a ‘criminogenic’ environment – whether this type of care environment helps to provide the conditions that produce crime or criminality. The paper draws on the findings from research on 10 children's homes in a large county local authority in England. The paper examines the patterns shown in trend data collected on problematic and offending data across these homes over a 7-year period, and a 1-year cohort study of 46 young people. Interviews with care staff and young people were used to contextualise these patterns. Findings revealed evidence of an environment where conflict and offending behaviour are common. It is suggested that the residential care environment, particularly for older teenagers, often presents a set of risks that tend to reinforce offending behaviour which reflects its last resort status.