Effective preparedness for and response to natural hazards includes knowing who is most at risk.  Heatwaves, due to their complex and pervasive nature, have not traditionally attracted the study due their importance in terms of human mortality.  For example, the bushfires of Black Saturday (2009) and Black Friday (1939) are remembered or known of: but who recalls the large scale heatwave events that preceded them?  Research utilising PerilAUS – Risk Frontiers’ database of historic natural hazard impacts – has quantified heat-associated deaths in Australia from European settlement to the present day.  Demographic trends and circumstances surrounding such deaths were analysed in order to inform the emergency services sector which groups of the population have been most at risk.  To date, figures indicate that, from 1844-2010, heatwaves have been responsible for at least 5 025 fatalities.  Data from 1900 onwards indicate they have killed more Australians than the combined total of deaths from all other natural hazards and that approximately 24% of these deaths have occurred in just nine large events.  Trends examined to date suggest that the overall decadal death rate has fluctuated over time and has decreased from a high of 1.40 per 100 000 population in the 1890s to its current rate of 0.23, with no clear trend apparent.  The male to female death-rate ratio has fluctuated over time from 7.7 in the 1900s to 0.5 in the 1990s: however, it does not approach equality.  Case studies were undertaken of five of the worst heatwave events in Australian history – 1896, 1908, 1939, 1959 and 2009 – to further explore any trends.  Policy implications in view of changing climate and societal conditions are discussed with respect to the trends analysis.