This paper presents a thermoeconomic analysis of the widely used and existing desalination processes. Thermoeconomic approach is used to distribute the cost of the whole process on the internal streams based on exergy not energy. The stream-cost equations are arranged in a matrix form and solved to calculate the monetary cost of the process streams. The cost associated with the rejected streams as well as the cost of the exergy destruction are calculated for process units. This in turn enables to point out the units which have the higher sum of investment and exergy destruction costs. Cost effective of the whole process recalling enhancement of these units. The most widely used desalination processes and especially are located in Suez Gulf region such as Multi stage flash (MSF), multi effect evaporation (MEE), thermal vapor compression (MEE-TVC), mechanical vapor compression (MEE-MVC), and reverse osmosis RO are considered and compared. This comparison is performed using developed Visual Design and Simulation (VDS) software. The results show that both Mechanical Vapor Compression (MEE-MVC) and Reverse Osmosis (RO) systems are in competition and they give lower unit product cost.