Peanut mottle virus (PeMV) causing mottling, yellowing, necrosis, malformation, and stunting was isolated from naturally infected peanut plants grown in El-Sharkiya Governorate. The virus was isolated mechanically and identified by indirect ELISA using both specific and induced polyclonal antiserum. Effect of virus infection on cell organelles, using electron microscopy, showed different degrees of degenerative changes in chloroplasts, mitochondria, nucleus, revealed amorphous and cylindrical cytoplasmic inclusions in infected leaf cells as pinwheel and laminated bundles. Pinwheel inclusion bodies are characteristic of Potyviruses which include PeMV. Two field experiments were conducted in 2006 and 2007 to study the effect of spraying sodium nitroprusside (SNP) and salicylic acid (SA) at 50, 100, 200µm of / 1 to induce resistance against PeMy infection in peanut plants (cv. Giza 5). All treatments induced resistance against PeMV-infection, when plants were sprayed before inoculation, with the virus. Also, all tested treatments gave a significant increase in photosynthetic pigments and activity of peroxidase (POD), ascorbate peroxidase (AS-POD), catalase (CAT), superoxide dismutase (SOD) and phenylalanine ammonia-lyase (PAL) compared with infected plants. Moreover, all treatments recorded increments in seed protein and oil contents at harvest time. Also, the total unsaturated and saturated fatty acids content increased in the treated peanut seeds compared with the untreated ones.