This paper aims to evaluate and compare the potential cost savings and greenhouse gas (GHG) reduction of district heating (DH) systems using heat from nuclear combined heat and power plants (NCHP) in Europe. Fifteen DH þ NCHP systems, spread throughout seven countries, are studied. The selection was made in collaboration with 'the Ad-Hoc Expert Group on the Role and Economics of Nuclear Cogene-ration in a Low Carbon Energy Future' from the Organisation for Economic Cooperation and Development. Firstly, the linear heat density of the modelled DH networks was determined, including locations with poorly developed DH networks. A large potential for extending DH networks was identified for France and the United Kingdom despite the expected decrease in the heat demand due to building renovation. Secondly, the costs and GHG emissions of DH þ NCHP systems were evaluated via a cost-benefit analysis. It concluded that 7 of the 15 projects would be cost-effective if 25% of the total urban heat demand was supplied. Implementing NCHP-based systems would reduce GHG emissions by approximately 10 Mt eCO 2 /a. Four additional DH þ NCHP systems could become competitive if a larger share of the total demand was supplied. Finally, a sensitivity analysis was performed to evaluate the uncertainty affecting the key parameters.