The changing demographic profile of the world's population towards old age and evidence of people living for longer with less time spent in ill health highlight the importance of addressing quality-of-life (QOL) assessment issues for older people. The assessment of health-related QOL (HR-QOL) has received considerable attention in the last 2-3 decades, with a wide variety of assessment instruments available. These instruments can be either generic or disease specific, health profiles or preference based. The literature was reviewed systematically to identify studies measuring HR-QOL in older patient groups. A total of 37 studies were identified, 11 of which were randomised, controlled trials/evaluations, 14 were prospective studies that did not involve a randomised, controlled intervention, and 12 were cross-sectional studies. Studies were summarised in terms of the study aim, patient population characteristics, the instrument used to measure HR-QOL, and HR-QOL findings. A majority of studies used a generic HR-QOL instrument, the single most commonly used being the 36-Item Short-Form Health Survey. In many cases, a second disease-specific measure was used in combination with the generic measure. In a majority of studies involving interventions, significant improvements in HR-QOL were noted. In prospective studies, a negative impact of health conditions (e.g. myocardial infarction and chronic heart failure) was also identified using HR-QOL assessments. None of the studies in this review used HR-QOL measurement instruments that were old-age specific. Using instruments that are not specific to a particular age group enables comparisons to be made with other age groups, i.e. younger or middle-aged groups. However, the questionnaire items of HR-QOL instruments tend to be phrased predominantly in relation to physical function and thus may inadvertently discriminate against older persons, whose physical function is likely to be not as good as that of younger people. Particular issues in the assessment of HR-QOL in older patient populations include the persistent finding of a poor relationship between QOL and disability/disease severity, the dynamic nature of QOL, and the importance of valid proxy ratings for those unable to make decisions or communicate for themselves. It is important, therefore, that assessment of HR-QOL incorporates issues of importance to individual older people by broadening the scope of the measurement instruments, thus representing more validly the HR-QOL status of older patient groups. Future research in HR-QOL must incorporate the perspective of the individual in order to enable valid conclusions to be derived based on content that is relevant to the individual being assessed, thus informing management decisions, policy and practice more meaningfully.