OBJECTIVES Patient-level utility values for different stages of MBC and toxicities commonly associated with chemotherapy regimens are useful for health economic assessments. Three methods to estimate utilities exist when direct utility data are not available: utility ‘mapping’ from existing disease-specific scales, vignette studies that describe the health states; or derivation of preference-based measures from an existing condition-specific scale. This study compares utility estimates in MBC utilizing the above methods. METHODS Based on data from a phase 3 clinical trial in MBC (N=1102) utility mapping was conducted using a published regression algorithm to convert the EORTC QLQ-C30 questionnaire to the EQ-5D utility. Mean utility values were estimated for relevant health states: stable disease (SD), tumor response (TR), disease progression (DP) and common toxicities. Results were compared to previously published values obtained for a vignette study conducted in one hundred members of the general public. RESULTS Observed MBC utilities were similar in mapping vs. vignette studies for SD: 0.697 vs.  0.715, and TR: 0.782 vs. 0.790. General public respondents in the vignette study assigned much lower utility to symptomatic DP (0.443) vs. imaging-based DP in mapping study (0.679); and disutility for  toxicities: vomiting: 0.103 vs. 0.050; fatigue 0.115 vs. 0.029; febrile neutropenia 0.150 vs. 0.012 (vignette vs. mapping respectively). Hand-foot syndrome, stomatitis and hair loss were not associated with disutility in the mapping study (potentially due to small sample size) while disutility of 0.116; 0.151; and 0.114 were reported by the vignette study. CONCLUSIONS Utilization of different methods to estimate utilities in MBC may lead to a wide range of estimated values with potentially significant implications for health economic evaluation. Caution must be exercised when comparing utility values derived using different methods. It is preferable to collect such data from patients directly and use vignettes as a last resort.