Ten years after the 2003 heat wave, heat waves remain a major public health concern. In light of the increased risk posed by climate change, the French Institute for Public Health Surveillance (InVS) organized an international and interdisciplinary workshop on heat vulnerability, a concept used by various stakeholders to identify the people or locations on which to focus prevention efforts and interventions. The workshop was organized into three sessions: the components of vulnerability, vulnerability indicators, and development needs. It highlighted the existence of a significant knowledge gap among the various stakeholders. Vulnerability depends on the complex links between individual sensitivity, exposure, and adaptive capacity. Through collaboration, meteorologists, epidemiologists, and sociologists can identify new opportunities for prevention. Spatialized vulnerability indicators, widely used in North America, offer interesting prospects for interdisciplinary collaboration. Health impact assessments also appear to be a relevant tool for evaluating the expected health benefits of development scenarios aimed at reducing urban heat islands. However, both of these tools require significant methodological development. (R.A.)