Susceptibility of four varieties of wheat ( Egypt 1, Egypt 2, Gemmiza 11and Sids 12), and five rice varieties ( Egypt 1, Egypt 2, Giza 179, Sakha 105 and Sakha 106) for infestation by  Sitophilus oryzae (L.) and Rhizopertha  dominica (F.) were evaluated in the laboratory at 28 ± 1ºc and 65 ± 5 % R.H. The results showed significant differences between various wheat varieties in the growth index of S .oryzae, it was comparatively higher in the varieties Gemmiza 11 and Egypt 1 than varieties Egypt 2 and Sids 12. Also, Egypt 1 was the least susceptible to R. dominica with lowest percent of weight loss (3.80%). In case of rice varieties data revealed that, Giza 179 and Egypt 2 varieties were the least susceptible to S. oryzae by lowest values of growth index (0.38 and 0.90, respectively ) and corresponding values of weight loss (0.16 and 0.38% ,resp.), with significant differences when compared with all  varieties. While, Sakha 105 variety was most resistance to R. dominica by growth index (1.27) and least value of weight loss (0.29%).A significant effect of grain  moisture contents on susceptibility/resistance against S. oryzae  and R. dominica .