The nuclear heating reactor (NHR) is designed with a number of advanced and innovative features, including integrated arrangement, natural circulation, self-pressurized performance, hydraulic control rod drive and a passive safety system. This paper presents a comparative economic assessment of a 200MW nuclear heating reactor with 2 middle scale nuclear (PWR600, PHWR600) and 2 fossil (CC600, GT600) power plants for the desalination of 160,000 m(3)/d water production using MED. The results indicated that the levelized discounted production of water cost in the case of NHR200 is $0.93/m(3), which is higher than that of the other 4 cases. But in the case of NHR200 there are great advantages in comparing its specific investment cost and total power plant investment cost with those of the other 4 cases. It was also proven that the NHR200 has an advantage in the power plant investment in a region while no electric grid connection is available for its safety system. Three sensitive factors for the cost of water desalination were analyzed and compared. The discount rate is one of the factors that has the greatest effect on the water cost. The levelized discounted cost of water produced from fossil fuel power plants is strongly influenced by the price of fuel. The nuclear option is just opposite.