[en] Cogeneration or Combined Heat and Power (CHP) is an advantageous technique based on the simultaneous utilisation of electricity and heat produced. For this purpose existing energetic technologies are used. Cogeneration is based on the thermodynamics principle that producing electricity by combustion process means, at the same time, producing waste heat that can be useful utilised. Three main advantages can be lay out in a cogeneration plant: 1. High efficiency (the global efficiency is often around 80-90%). 2. Economic profit (pay back time is usually not longer than 2-4 years). 3. Low pollutant emissions (as a consequence of the high efficiency less fuel is burned for generating the same quantity of electricity). In this report are analysed various aspects of cogeneration (technical and economical) and the conditions influencing is development. Some figures on the european and national situation are also given. Finally are presented the research and development activities carried out by Italian National Agency for new Technology Energy and the Environment Energy Department to improve the efficiency and the competitiveness of this technology