With the increasing prominence of the patients' involvement in the care they receive, the assessment of outcomes based on the patient's perspective using patient-reported outcome measures (PROMs), are increasingly accompanying the traditional clinical ways of measuring health and the effects of treatment on the patient. This article provides an overview as to what PROMs are and the different health constructs they are purported to measure. Differences between generic and disease-specific, multidimensional and index scored PROMs are also described. Factors relating to the choice of a PROM are discussed with a particular focus on the importance of developing a measurement strategy and endpoint model to ensure the appropriate PROM is selected to measure the desired outcome. Examples of the application of PROMs are given together with some of the methodological approaches to interpreting PROM data. Finally, issues on maximizing the benefits of using PROMs are briefly discussed.