Libya is an and and water scarce country. The main source of water is ground water, which is limited and over exploited. The deficit is increasing and certain measures must be taken to resolve the problem. Unconventional sources such as sea water desalination was seriously considered since mid seventies, to cover part of the deficit. The total accumulated installed desalination capacity fill the year 2000 is about 750,000 m(3)/d. Thermal processes represent about 72% and the rest are membrane processes. While the design capacity of the operable desalination plants in the year 2002 is about 332,930 m(3)/d, where thermal processes represent about 63% and the rest are membrane processes. The shares of desalination in the overall water supply represent 1.4% in the year 2002. A plan to construct about 13 desalination plants with a total installed capacity of 705,000 m(3)/d was adapted. Some of the plants are in the contracting stage and the others are under study. Low utilization factor and high capital investment are affecting negatively the desalted water unit cost. The average unit cost of desalted water is 2.69 $/m(3), which is very high. Economical strategies should be developed to reduce production cost taking into account all phases from site selection and design to operation and maintenance.