Irrigation in Tunisia is threatenedall over the country. The irrigated coastal area of Dyiar-Al-Hujjej has observed a drop-in agricultural activity following a seawater intrusion. Thus, yields have become disrupted in direct relation to the quantities of fresh water supplied and transferred over a distance of 100 km. For the sustainability of this perimeter, the feasibility of using desalinated water to stabilize the irrigation water supply was analyzed. When all crops water requirements are to be met with desalinated water, the net income is negative for all crops currently grown, except strawberry. All the open-field crops remain unprofitable even in the case of agro-industrial development, except tomatoes. A blending between desalinated seawater and aquifer saltwater leads also to a negative income for the main crops. The introduction of greenhouses to replace the same open-season crops is beneficial when desalinated water is used. The use of desalinated water in irrigation faces the high cost of desalination (0.5 US $/m3) while the average price of irrigation water in Tunisia is 0.05 US $/m3. Desalination can be recommended only in the case of crops with low need for water and high added value.