The Intergovernmental Panel on Climate Change has clearly stated that climate change is occurring and temperature extremes and heatwaves will be more frequent. In Melbourne, this may include a 10-40% increase in heatwave days by 2030. Published literature has identified the elderly, infirmed and the very young as being most susceptible to heatwave conditions. We need to locate groups within our population who are most vulnerable to adverse health outcomes associated with extremely hot weather in order to develop effective adaptation and mitigation strategies. This project used multiple social, health and environmental sources of information to create an index of vulnerability for Melbourne. This index was mapped to create a spatial representation of vulnerability in Melbourne. The index was tested using daily numbers of deaths and hospitalisations and meteorological data for predefined temperature thresholds to assess its effectiveness in identifying the location of populations susceptible to heat events. By providing information about population vulnerability to heat exposure from a social, demographic, health and environmental perspective this study created the opportunity to target behavioural adaptation, public health responses to heat events, and specific information about health risk for urban planners. The research tool itself is not Melbourne specific and can easily be transferred to other Australian cities.