OBJECTIVES: The aim of the current study is to quantify mental health-related emergency department (ED) presentations and hospitalisations, and associated child and family characteristics, in children recruited through four Aboriginal Community Controlled Health Organisations. SETTING: Four Aboriginal Community Controlled Health Services that deliver primary care. All services were located in urban or large regional centres in New South Wales, Australia. PARTICIPANTS: 1476 Aboriginal children aged 0-17 years at recruitment to the Study of Environment on Aboriginal Resilience and Child Health. PRIMARY OUTCOME MEASURES: ED presentations and hospital admissions with a primary mental health diagnosis obtained via linkage to population health datasets. RESULTS: Over a median of 6-year follow-up, there were 96 ED presentations affecting 62 children (10.7/1000 person-years) and 49 hospitalisations affecting 34 children (5.5/1000 person-years) for mental health conditions. Presentations/admissions increased with age. ED presentation was increased with: living in foster versus parental care (adjusted rate ratio (RR)=3.97, 95% CrI 1.26 to 11.80); high versus low baseline child emotional/behavioural problems (adjusted RR=2.93, 95% CrI 1.50 to 6.10); and caregiver chronic health conditions versus none (adjusted RR=2.81, 95% CrI 1.31 to 6.63). Hospitalisations were significantly increased with caregiver unemployment versus home duties (adjusted RR=4.48, 95% CrI 1.26 to 17.94) and caregiver chronic health problems versus none (adjusted RR=3.83, 95% CrI 1.33 to 12.12). CONCLUSIONS: Tertiary care for mental health issues was relatively common among participating Aboriginal children, with risk elevated for those living in foster care, with prior mental health and behavioural problems and with carers with chronic illness and/or unemployment. While this study suggests high rates of serious mental health events among children from participating communities, the optimum means for reducing these rates, and the need for tertiary care, has not yet been determined. Such information is urgently required to inform policy and programmes to support Aboriginal child and adolescent mental health.