The rising prevalence of children with chronic conditions has made quality of life an increasingly important outcome measure in paediatric practice. The discrepancy between doctors' and patients' perceptions of quality of life makes formal assessment necessary. In this paper we use a case scenario to answer commonly asked questions. What is quality of life and who can assess it? Why assess quality of life in the clinical setting? Is it feasible to measure in routine clinical practice? How is quality of life formally assessed? We provide a basic outline of the language and methods of quality of life assessment and use the case scenario to discuss the process of choosing an appropriate instrument. We conclude that quality of life assessment in clinical practice is feasible and provides benefits for both patients and doctors. The benefits include better informed doctors, improved patient doctor communication and a means to effectively monitor quality of life as a treatment outcome.