Background: On 1 January 2006 a number of far-reaching changes in the Dutch health insurancesystem came into effect. In the new system of managed competition consumer mobility plays animportant role. Consumers are free to change their insurer and insurance plan every year. The ideais that consumers who are not satisfied with the premium or quality of care provided will opt fora different insurer. This would force insurers to strive for good prices and quality of care.Internationally, the Dutch changes are under the attention of both policy makers and researchers.Questions answered in this article relate to switching behaviour, reasons for switching, anddifferences between population categories.Methods: Postal questionnaires were sent to 1516 members of the Dutch Health Care ConsumerPanel and to 3757 members of the National Panel of the Chronically ill and Disabled (NPCD) inApril 2006. The questionnaire was returned by 1198 members of the Consumer Panel (response79%) and by 3211 members of the NPCD (response 86%). Among other things, questions wereasked about choices for a health insurer and insurance plan and the reasons for this choice.Results: Young and healthy people switch insurer more often than elderly or people in bad health.The chronically ill and disabled do not switch less often than the general population when both populations are comparable on age, sex and education.For the general population, premium is more important than content, while the chronically ill and disabled value content of the insurance package as well. However, quality of care is not importan tfor either group as a reason for switching.Conclusion: There is increased mobility in the new system for both the general population and the chronically ill and disabled. This however is not based on quality of care. If reasons for switching are unrelated to the quality of care, it is hard to believe that switching influences the quality of care. As yet there are no signs of barriers to switch insurer for the chronically ill and disabled. This ...