The objective of the study was to evaluate the reliability, validity and responsiveness of two generic multiattribute methods for measuring utility for health states: a 15-dimensional (15D) and a five-dimensional method (EuroQol and EQ-TTO). A self-administered questionnaire with both measures was used in 59 outpatients with chronic obstructive pulmonary disease and the findings compared with standard gamble (SG) and time trade-off (TTO) utilities, spirometry and arterial blood gases. Quality of life scores were smallest for EQ-TTO (median 0.73) and highest for SG and TTO (median 0.91 and 0.95 respectively), while 15D gave intermediate values (median 0.80). The test-retest reliability over 14 days was: 15D (p = 0.90) and EQ-TTO (p = 0.73), using Spearman's rank correlation. 15D was better than EQ-TTO at discriminating between groups of patients after reported global rating of change over 12 months (P = 0.004 versus P = 0.09), indicating that 15D was more responsive. The 15D instrument has many attractive properties when compared to the EQ-TTO method, including a better reliability and responsiveness. Validity depends on validation method. The findings in this study indicate that the different utility measures measure different aspects of health-related quality of life (HRQoL). Caution should be taken when choosing utility instruments in cost-utility studies, as this can strongly influence the results.