The factors that may lead to an impaired quality of life in congestive heart failure (CHF) are physical symptoms, psychological problems, treatment adverse effects and social limitation. There are now several general and disease-specific quality-of-life (QOL) questionnaires which have been used to measure treatment effects in clinical trials in CHF. We review the design and validation of both generic and disease-specific QOL questionnaires which have been used in clinical trials in CHF. We then evaluate the performance of these QOL questionnaires in recent clinical trials in CHF in relation to other outcome measures. We conclude that there are important differences between these QOL questionnaires. The choice of a QOL questionnaire is relevant to both patient compliance and clinical outcomes in CHF trials. The 36-Item Short Form (SF-36) Health Survey, a generic QOL questionnaire, and the Minnesota Living with Heart Failure questionnaire, a disease-specific QOL questionnaire, have returned informative data in most trials in which they have been used. QOL questionnaires require further development if this important outcome is to be reliably measured in future clinical trials in CHF.