In Sweden and other countries, the benefits of user choice and market forces are often voiced in relation to the provision of medical care and social services. Policy makers increasingly view people as customers and consumers of care services. Among very old people-the most frequent care users-how many have the capacity necessary to find information and make decisions concerning providers of medical and social services? Using a nationally representative sample of Swedes aged 77+ (SWEOLD) in 2002 this study describes the prevalence of cognitive, physical and sensory resources associated with the capacity to make and carry out informed choices concerning medical and social care providers. Results showed that one third of a nationally representative sample of persons aged 77+ scored low on a cognitive test or they were so cognitively impaired that they could not be interviewed directly. Another 22% scored poorly on a test of the ability to find and process information. A further 32% had adequate cognition but had limitations in sensory function or mental vitality or were unable to go outside on their own. A total of 10% did not report any of the measured problems. In general, care utilisation increases with age. As health problems increase, physical and cognitive abilities decline. Results suggest that those elderly people who are most dependent on care services and who could benefit most from a "good choice", are also those who have the highest prevalence of cognitive and physical limitations associated with the capacity to act as a rational consumer of care services.