Quality of life research is an emerging science of particular relevance to clinical cancer research. The development and utilization of valid and reliable quality of life measures as outcome parameters may profoundly alter the clinical trials process. Such measures, contrary to prevailing opinion, may be as accurate and precise as conventional measures, but considerably more relevant to the trials process. However, lack of rigor in the evaluation of such indices and uncritical interpretation of results may seriously compromise the credibility of the concept. This overview of the current status of quality of life research is designed to provide a perspective from which to evaluate ongoing development.