PURPOSE: To evaluate the association between quality-of-life (QOL) impairment as reported by patients and QOL impairment as judged by nurses or physicians, with and without consideration of spiritual well-being (SWB). PATIENTS AND METHODS: A total of 163 patients with advanced cancer were enrolled onto a therapeutic trial, and cross-sectional data were derived from clinical and demographic questionnaires obtained at baseline, including assessment of patient QOL and SWB. Clinicians rated the QOL impairment of their patients as mild, moderate, or severe. Clinician-estimated QOL impairment and patient-derived QOL categories were compared. Correlation coefficients were estimated to associate QOL scores using different instruments. The analysis of variance method was used to compare Functional Assessment of Cancer Therapy-General scores on categorical variables. RESULTS: There was no significant association between self-assessment scores and marital status, education level, performance status, or predicted life expectancy. However, a strong relationship between SWB and QOL was noted (P <.0001). Clinician-estimated QOL impairment matched the level of patient-derived QOL correctly in approximately 60% of cases, with only slight variation depending on the method of categorizing patient-derived QOL scores. The accuracy of clinician estimates was not associated with the level of SWB. Interestingly, a subset analysis of the inaccurate estimates revealed an association between lower SWB and clinician underestimation of QOL impairment (P =.0025). CONCLUSION: Clinician estimates of QOL impairment were accurate in more than 60% of patients. SWB is strongly associated with QOL, but it is not associated with the overall accuracy of clinicians' judgments about QOL impairment.