Quality of life (Q/L) measurements are used to justify or refute different forms of medical treatment; to identify the sequelae of disease or treatment which are resolved by other interventions including nursing and to provide a basis for allocating resources to those treatments judged to be most cost-effective. This paper reviews some of the difficulties in defining and measuring Q/L and the ethical issues raised in relation to their use in allocation of treatment resources. It is suggested that Q/L tests should include a range of dimensions known to contribute to Q/L and that they are applied at different times during the progression of illness and incorporate information obtained from patients. It is essential that weightings by individuals of dimensions investigated in the test are included. Further research is necessary to determine the effects of coping strategies and personality variables on Q/L.