This paper addresses the question of how well quality of life measures function as valid and sensitive outcome indicators of mental health services. Findings from the major empirical studies of quality of life in the mental health area over the last 15 years are reviewed. The extent to which existing studies provide evidence of the ability of quality of life measures to discriminate the impact of service interventions on the well-being of psychiatric clients is examined. Findings from cross-sectional, comparative, repeated-measures and randomised studies are presented. The available empirical evidence is critically examined and the methodological and theoretical implications of current findings for future Work are considered.