Rice blast is the most important disease in Egypt and worldwide. The rice blast is caused by P y ric ula ria g ris e a this fungus can produce physiological races. Development of varietal resistance is the most effective way to control rice blast. This study was focused on identification of 20 isolates and evaluation of 21 rice genotypes for blast disease. Also, determining the biochemical changes after inoculation with the blast pathogen. The isolates were identified as five groups, IC group race the common followed by ID and only one race for each IA, IB and IF. Evaluation for genotypes showed that the first and second groups were resistant to blast infection. However, the third group showed 70 to 75% resistant. Biochemical changes included determination of antioxidant enzymes (Peroxidase (POX) and Ascorbate peroxidase (APX), defenserelated enzymes (Phenylalanine ammonia layase (PAL) and chitinase) and salicylic acid (SA). The different enzymes increased 96 h after inoculation with the pathogen and then decreased. The enzymes content was increased in inoculated seedling compared with the un-inoculated ones. The highest SA content was found in Giza 178 rice cultivar.