To evaluate the protein response of barley cultivars under salinity stress, leaf samples were prepared at 0, 3, 6, 9, 12 and 15 days after the tillering stage. Following two-dimensional electrophoresis, 153 and 141 protein spots were identified in tolerant (Afzal) and sensitive cultivars (Macouei), respectively. In total, 21 and 17 spots with significant induction factor (IF) were revealed in Afzal and Macouei, respectively. Most common proteins between two cultivars were involved in the removal of antioxidants (five proteins), and for each protein group including heat shock, proton transfer, Calvin cycle and photosynthesis optical reaction proteins, a protein was detected. Also, 12 protein spots were exclusively present in tolerant cultivar (Afzal), most of them involved in the elimination of antioxidants, and eight protein spots were found exclusively in sensitive cultivar (Macouei), which was also largely involved in the removal of antioxidants. Lower expression of these proteins in the susceptible cultivar compared to tolerant cultivar resulted in decreased homeostasis in susceptible cultivar under salinity stress. Also, for most proteins, the highest and lowest protein expression levels occurred in tolerant and susceptible cultivars at 12 and 9 days after initiation of salinity stress. Manuscript profile