Peanut (Arachis hypogaea L.) is considered to be one of the most important edible oil crops in the world as well as in Egypt. In the present study, tissue culture protocol was established in peanut varieties and the in vitro selection was applied to assess the possibility of obtaining salt tolerant peanut plants via tissue culture. In addition, the change in gene expression under salinity stress as revealed by protein pattern analyses was also studied. Callus and shoot regeneration were decreased with the increment of NaCl level from 50 to 150 mM in the culture medium. At higher concentration of NaCl (200mM), the cultured explants turned brown and the few developed calli failed to regenerate shoots or regenerated abnormal shoots with very low frequency in all tested varieties. A total of 1760 embryonated cotyledons from Giza-5, Gregory, Giza-7 and Giza-6 were cultured under selection conditions of salinity stress (150 mM NaCl). The selected and unselected regenerated plants in comparison to their donor parents were tested for salinity tolerance in vitro by culturing on medium supplemented with 0.0 and 150mM NaCl. The selected plants showed significant enhancement in their growth under salinity treatment, as compared with the unselected plants and their donor parents. Salinity stress treatment lead to differential expression of the genetic information in peanut, resulting from changes in gene products, including the synthesis of four new proteins and simultaneously reduced the expression of 8 proteins in the tested varieties. The newly synthesized proteins may play an important role in the mechanism(s) of salt tolerance in peanut.