Aim: To measure comprehensive medical assessment (CMA) completions among aged care residents in Australia; and to report the outcomes of a CMA service trial. Methods: A population-based descriptive study of CMA completions using Medicare data; and a qualitative study of an intervention trial carried out at a 115-bed residential aged care facility in Sydney, Australia. Fifty residents participated in the trial; 15 interviews were conducted. Results: In 2008, less than 50% of Australian aged care residents had a CMA completed. The CMA service trial improved CMA data quality and accessibility. A substantial proportion of residents were found to have previously unidentified health problems that impacted on their health and quality of life. Conclusions: CMA rates are low. New approaches to achieving higher CMA rates, utilising information technology, hold promise. Strategies for ongoing monitoring of care to follow-up problems identified are required to achieve measurable improvements in residents' care and quality of life.