Following the heat wave of August 2003 that caused over 70,000 fatalities in Western Europe, heat-health action plans (HHAP) and heat warning systems were implemented in many European countries, including Germany. The effect of these preventive measures (informing the population as well as nursing and medical personnel) on excess mortality during heat waves in Frankfurt am Main, Germany, is studied, taking into account newly published data on a modifying effect of air pollution on heat mortality. MATERIAL AND METHOD: Mortality data comprising all deaths registered in the city of Frankfurt was obtained from the statistical state office; air temperature and air pollution data in Frankfurt Ost were obtained from the Hessian state office for environment and geology. SPSS Version 15 was used for statistical analysis (bivariate and partial correlations, nonparametric tests/Kruskal-Wallis, and Mann-Whitney test). RESULTS: Temperature data as well as air pollution and daily mortality exhibited extreme values in summer 2003 compared to the summer periods 2004-2013. Never again were such levels of temperature and air pollution reached. In 2003, excess mortality was 78%, and as high as 113% among the population aged >80 years. During the heat wave of 2010, the total excess mortality was 23% (significant) and 38% in the population aged >80 years, while during heat waves in 2006 and 2013 no significant increase in total mortality was seen (total excess mortality 12% and 4%; not significant). CONCLUSION: Lower excess mortality could be seen in Frankfurt am Main during heat waves following the implementation of HHAP and the heat warning system. This might be an effect of the measures implemented by the HHAP to reduce heat mortality. However, it cannot be ruled out that this might also be an effect of shorter heat wave periods and lower air pollution in the subsequent years. Therefore, further efforts are needed to improve the resilience of the population, especially the elderly population, to better cope with heat waves.