MAA1-O-10 After the 2003 heat wave, great attention has been paid by the Italian government to reduce the impact of extreme temperatures on human health. In 2004, the Italian Department for Civil Protection implemented a 3-year national project for the prevention of heat-health effects during summer. The main objectives of the project are: the implementation of city-specific warning systems (HHWWS), the development of “real-time” surveillance systems for monitoring the impact of heat on mortality and to evaluate the performance of warning systems, and the introduction of national and local prevention programs. By 2005, HHWWS. were operational in 7 cities and, by 2006, a total of 13 cities will be operational and 6 more experimental. Warning systems and mortality surveillance systems are activated from the 15 May to 30 September in all cities. At a national level, the National Centre for Prevention of Heat Health Effects coordinates the project and is responsible for data collection, the running of surveillance systems, as well as the development and elaboration of the warning systems for the production of daily warning bulletins. Warnings are distributed throughout the network to all the local centers, where the local center in charge (civil protection, municipality etc) coordinates the local information network and activates prevention programs. Three different methodologies were identified for the development of city-specific warning systems. Air mass-based models were constructed for the largest cities using the synoptic approach to identify oppressive climatic conditions associated to an increase in mortality. Autoregressive models, based on previous day mortality data, retrieved from the surveillance system, as well as weather forecast data were introduced for Bologna, Milan, Rome, and Turin. Finally, temperature threshold models were developed for smaller cities. These Poisson regression models identify the level of maximum apparent temperature above which an increase in mortality (≥65 years) is observed. Descriptive results and an evaluation of the different HHWWS models of the summer 2006 will be presented.