This review begins with an outline of outcome measurement in the country where it has been most thoroughly implemented, namely Australia. There follows a consideration of what constitutes an outcome in mental illness generally, and chronic mental illness in particular. Some instruments, such as the Health of the Nation Outcome Scales (HoNOS), focus primarily on illness severity, and examples of their use in the area of chronic mental illness are presented. Other instruments, such as the Life Skills Profile (LSP), assess personal functioning or disability, and that literature is reviewed. One major area of attention in the chronically mentally ill is quality of life. Another fruitful approach to assessing outcome is to look at needs, especially unmet needs, for which the leading instrument is the Camberwell Assessment of Need; relevant findings are reviewed. The most recent area of interest is recovery. While several scales have been developed, there are as yet relatively few reports of their application with patients with chronic mental illness. The concluding section considers the benefits and weaknesses of using the same standard instruments with all consumers within a service, and shows the utility of outcome results in groups and individuals with generally small overall changes.