Children who spend time in care are more likely to have an official record of offending behaviour than the general population. However, there is a lack of longitudinal research on the timing, severity, and volume of offending in relation to time spent in and out of care. Furthermore, differences in patterns of offending by identifiable groups in care are rarely a focus of research.This study is both longitudinal and identifies 8 groups within the care population with different volumes of recorded offending: ranging from a mean of 41.75 (prolific) to 1.60 (low). Substance misuse, gender, and reasons for referral to care were associated with different patterns of offending in and out of care. The study is primarily based on a subsample of 64 children who had offended whilst in care. The subsample represents 38.5% of a cohort of children who had been in care or were taken into care over a particular period (2008)(2009)(2010)(2011) in one local authority.The placements and recorded offences of the 64 children were tracked for a further 2 years (2011)(2012)(2013). The study highlights future areas of research and the need for more tailored responses to different groups within the care system. . In recent years, more children are spending some time in care and the rate per 10,000 children younger than 18 years has increased from 54 to 60 between 2009.Taylor (2003) argues that the relationship between care, troublesome behaviour, and criminal careers has often been taken as a given, without being properly understood and evidenced. Young people in care are not a homogenous population; they spend very different amounts of time in and out of care, in different types and combinations of placement; and they bring with them different combinations of issues that may intersect with their vulnerability to getting into trouble. Fitzpatrick, Williams, and Coyne (2016) argue that many of the issues that relate to how the criminal justice system interacts with children in care and care leavers cannot be neatly dealt with. They argue that these issues connect with broader policy, such as the age of criminal responsibility in England and the support provided for care leavers. Narey (2016) highlights other issues such as Home Office counting rules and police discretion in relation to responses to police call-outs to residential care. In other words, the broader policy setting in which young people in care get a record of offending behaviour is part of the problem, and it can conflict with targeted initiatives aimed at reducing the number of children in care with a record of offending.The current empirical study is framed by broader theoretical explanations relevant to offending behaviour and children in care and key research evidence on the prevalence of offending behaviour by children in care (specifically longitudinal research). The study sets out to answer five research questions. First, what is the prevalence of offending behaviour amongst children and young people who have spent time in care? Second, do young people com...