Children living in public care are more vulnerable to mental and physical health morbidity than their peers living within birth families. The aetiology is complex but pre-care health neglect and abuse, genetic predisposition and the subsequent instability experienced within public care are key contributory factors. Conduct disorder is the commonest mental health problem described. If conduct-related behavioural problems are the defining feature of a child’s difficulties, promoting good physical health becomes particularly challenging. Equally, anxiety and affective disorders can easily be overlooked during physical health consultations. Services must work closely across specialist professional boundaries to promote health in the spirit of the Children Act (1989) as ‘a positive state of mental physical and spiritual wellbeing’. This article describes the evidence for co-morbidity of physical and mental health problems and highlights the importance of close working across mental and physical health services.