The economy of combined nuclear power stations generating electric power and district heat is evaluated by comparing their generation costs with those of conventional fossil-fired dual-purpose stations. Realistic assumptions on several technical and economic variables and parameters (heat/power ratio, investment and fuel costs, heat transport costs) for both the nuclear and the conventional alternative were derived from the present situation and for the foreseeable future. Only light water reactor technology, with its safety standard presently approved only for remote location, was considered, therefore causing the necessity of long-distance heat transport. If only the generation costs are considered, the results show that from the economic point of view the nuclear plants are well competitive with the fossil-fired stations. However, if we add the costs for the long-distance transport of nuclear heat, this economic advantage is rapidly compensated by the transport costs with increasing distance. Only very large nuclear plants—not suitable for the size of presently existing distribution systems—can economically overcome the minimum safety distance of 20 to 30 km.