Resistance of barley to powdery mildew has been studied using 20 near-isogenic lines to identify gene (s) conditioning resistance. The data indicated that the genes ML-a+?, ML-a6, ML-a14, ML-a7+?, and MI, (La) are effective against powdery mildew in Egypt. Screening harley genotypes revealed that three genotypes showed resistance at both seedling and adult stages. About 59 genotypes (local material) and 182 (exotic material) were selected as powdery mildew resistant under field conditions. Leaf rust resistance was 44 genotypes from the local materi­al and found in 53 from the exotic material. Net blotch-resistant geno­types selected under field conditions, were 24 from the local material and 68 from the exotic material.