Public values must play a substantial role in any attempt to deal with the health care resource allocation problem. This article examines how preferences for the health outcomes of care (e.g. improved or worsened physical suffering) can provide a coherent basis upon which set explicit health care priorities. Preferences for health outcomes could be mapped onto information concerning the outcomes expected from the specific health services when used for particular clinical conditions. These 'preference-weighted' outcomes would determine the relative priority given to health services for each specific condition. Generic outcome measures would be used in order to permit comparison of benefits and harms across different services. It is argued herein that allocation rules cannot be based on individual patients' preferences. Instead, average population preferences should be used to evaluate the relative importance of services--as occurs in other insurance contexts--despite theoretical concerns about the aggregation of preferences. Patients' preferences might also be estimated by reference to relevant demographic factors, but only if population subgroups are identified with relatively homogeneous preference patterns and if the use of such subgroups is deemed socially acceptable. Concerns about stereotyping and discrimination might limit the tractability of this approach.