Abstract: A greenhouse experiment was carried out to determine the effect of saline irrigation on biomass yield, protein, phosphorus (P), potassium (K), calcium (Ca) and magnesium (Mg) composition of four barley (Hordeum vulgare L.) cultivars in a pot experiment. Mean biomass yield (drymatter) decreased significantly with increasing irrigation water salinity. The drymatter yield ranged between 56.1 g per pot (Qatifi) with water EC of 2.85 dS m-1 to 11.5 g per pot (Gusto) with water EC of 15.95 dS m-1. The trend of biomass yield reduction among various cultivars (drymatter) was Gusto > Alkharji > Haili > Qatifi. Overall sequence of salt tolerance for different barley cultivars was Qatifi > Haili > Alkharji > Gusto. Mean protein contents ranged between 14.5-29.5% (Qatifi), 16.12-20.3% (Haili), 15.5-21.3% (Gusto) and 16.3-22.7% (Alkharji) among various barley cultivars receiving waters of different salinities. Mean concentration of different macro-elements in barley plants were 0.15-0.27% P, 2.2-4.6% K, 0.9-2.9% Na, 0.41-0.99% Ca and 0.31-0.82% Mg. The concentration of protein, sodium, calcium and magnesium increased while that of phosphorus and potassium decreased in barley plants increasing salinity of irrigation water. A comparison among different cultivars indicated that irrigation waters with EC of 13.75 dS m-1 and above reduced biomass yield to a significant level. In conclusion, there is an excellent potential for reasonable production of barley as forage crop containing appreciable protein contents and other essential mineral elements with irrigation water of EC upto 9.72 dS m-1 provided 15-20% extra water above crop water consumptive use is applied as leaching requirements to control soil salinity.