This paper presents a complete analysis of the state of the art and the legislation of distributed generation in Italy, which is similar to other EU countries, and statistic data on combined heat and power plants installed in Italy. Data was collected from a large number of sources, because most of the small size plants are operated by IPP without an electrical exchange contract with the grid and are not documented. The results of this research has allowed to show that 22.000 MW can be generated by over 1600 power plants spread over the Italian territory. A more detailed analysis and validation of the information was done with reference to Umbria, a central Italian region. The whole database was examined with several correlations in order to facilitate the analysis of the national situation. It is thus possible to query the database in order to determine the types of users, the typical size for different users and their geographic distribution. This tool is extremely helpful in the design of new power plants and in the definition of the potential future market.