The Clinical Significance Consensus Meeting Group of the Symposium on the Clinical Significance of Quality-of-Life Measures in Cancer Patients produced 6 articles regarding the clinical significance of quality of life (QOL) assessments in oncology. The 6 articles deal with the methods used to date: group-vs-individual clinical significance; single items vs summated scores; patient, clinician, and population perspectives; assessment of changes over time; and communication of results. The articles were produced by a team of 30 QOL research experts assembled in a consensus writing meeting held at the Mayo Clinic, Rochester, Minn, October 6 and 7, 2000. This introduction describes the need for the articles, definitions of key terms, and plans for the future. It is hoped that this series of articles will serve as a resource for individuals conducting cancer QOL research and for clinicians considering incorporation of QOL assessment in the treatment of patients with neoplastic diseases. A secondary goal is to stimulate further discussion and research in the interpretation of QOL assessments.