The 2005 Health Barometer is intended for all public health stakeholders and decision-makers who wish to deepen their understanding of the population’s health, as reported and perceived by the population itself. It describes the behaviors, attitudes, knowledge, and opinions of people aged 12 to 75 regarding health. With its sample of 30,000 people and its methodology, the 2005 Health Barometer stands as a benchmark for high-quality telephone surveys. Sixteen chapters cover a wide range of topics, such as psychoactive substance use, cancer screening, vaccination, quality of life, accidents, physical activity, sleep, and the link between health and work. This study also highlights significant disparities within the population and thus provides a quantitative framework for addressing the issue of health inequalities.