The past 5 years have seen increasing application of health-related quality-of-life (HRQOL) assessment in oncology. Most commonly, HRQOL has been studied in patients with metastatic cancer and in trials involving the use of antiemetics to control postchemotherapy nausea and vomiting. These studies have produced interesting and, in some cases, counterintuitive results. Thus far, HRQOL assessment appears to be important in clinical trials involving control of symptoms (disease-related or treatment-related), cancers with a poor prognosis, treatment arms with similar survivals, supportive care interventions, and ways of determining prognosis.