To characterise the socio-demographic characteristics, aged and health care needs, and aged care services used by older Aboriginal and Torres Strait Islander people assessed for aged care service eligibility. Population-based retrospective cohort study; analysis of Registry of Senior Australians (ROSA) National Historical Cohort data. Aboriginal and Torres Strait Islander people aged 50 years or older who were first assessed for aged care service eligibility (permanent residential aged care, home care package, respite care, or transition care) during 1 January 2017 - 31December 2019. Socio-demographic and aged care assessment characteristics; health conditions and functional limitations recorded at the time of the assessment; subsequent aged care service use. The median age of the 6209 people assessed for aged care service eligibility was 67 years (interquartile range [IQR], 60-75 years), 3626 were women (58.4%), and 4043 lived in regional to very remote areas of Australia (65.1%). Aboriginal health workers were involved in 655 eligibility assessments (10.5%). The median number of health conditions was six (IQR, 4-8); 6013 (96.9%) had two or more health conditions, and 2592 (41.8%) had seven or more. Comorbidity was most frequent among people with mental health conditions: 597 of 1136 people with anxiety (52.5%) and 1170 of 2416 people with depression (48.5%) had seven or more other medical conditions. Geriatric syndromes were recorded for 2265 people (36.5%); assistance with at least one functional activity was required by 6190 people (99.7%). A total of 6114 people (98.5%) were approved for at least one aged care service, 3218 of whom (52.6%) subsequently used these services; the first services used were most frequently home care packages (1660 people, 51.6%). Despite the high care needs of older Aboriginal and Torres Strait Islander people, only 52% used aged care services for which they were eligible. It is likely that the health and aged care needs of older Aboriginal and Torres Strait Islander people are not being adequately met.