Introduction: To provide optimal care for patients with chronic obstructive pulmonary disease physicians need to understand if their patients benefit from an intervention. The objective of this study was to assess agreement between patients and physicians on health-related quality of life (HRQL) changes in response to respiratory rehabilitation and to explore sources for disagreement. Methods: Sixty-one patients rated their health states on a validated preference-based instrument, the feeling thermometer (FT). In an analogous manner, the eight treating physicians rated the patients' health states on the FT. Patients and physicians were blinded to each other's ratings. We calculated intraclass correlation coefficients (ICC) to assess agreement between patients and physicians and used HRQL instruments and the 6-min walking test to assess the evaluative properties of the FT. Results: We found moderate agreement at baseline (ICC 0.40, P=0.018) and follow-up (ICC 0.49, P=0.008) but large disagreement about change scores (ICC 0.02, P=0.46). Patients' FT change scores correlated well with change scores of the Chronic Respiratory Questionnaire, SF-36 and the Borg scale for dyspnoea whereas physicians' FT change scores correlated significantly with the change score of the 6-min walking test (r=0.33). Physicians' ratings showed an inconsistent pattern for correlations with HRQL measures. Conclusions: There is large disagreement between patients and physicians on HRQL changes in response to respiratory rehabilitation. Investigators should assess whether the introduction of HRQL instruments into clinical practice raises the awareness of physicians towards HRQL and improves agreement with their patients. © 2004 Elsevier Ltd. All right reserved.