Puccinia striiformis Westend is an obligate parasite, has the capabilities to infect wheat (Triticum aestivum) and barley (Hordeum vulgare) causing yellow (stripe) rust, which is extremely a very dangerous disease. Several formae specialis of the rust fungus P. striiformis, including P. striiformis f.sp. tritici (Pst) and P. striiformis f.sp. hordei (Psh), are classified based on host specialization. In 1920, P. striiformis f.sp. tritici (Pst), which causes wheat stripe rust, was discovered for the first time in Egypt (Briton-Jones, 1920 and Briton-Jones, 1925). In 2022, wheat varieties, Gemmeiza-11, Sids-12, Misr-1 and Misr-2 are susceptible to yellow rust, meantime symptoms of yellow rust caused by P. striiformis f.sp. tritici were observed on barley line, Sawsan/Badia//Arar/3/Gloria'S'/Copal'S'/6/Rhn-03/Eldorado/5/Rhn-03//Lignee527/NK1272/4/Lignee527/Chn-01/3/Alanda for the first time in the Smart Agricultural Clinic Project plots area at Sakha Agricultural Research Station (hot spot) (Fig. 1). Yellow pustules aligned linearly between the lateral veins bundles of leaves are among the disease symptoms as well as the glumes are filled by the fungus uredospores (Fig. 1.A, B, D, E, C and F). Yellow rust symptoms typically appeared early in the 2022 season and caused severe epidemics because of the availability of suitable climatic conditions (low-temperature and high humidity %). The isolates collected from infected barely leaves were virulent on the wheat differential variety; Chinese 166 at seedling stage under greenhouse condition. Also, the obtained results showed virulence's to Yr1, Yr17, Yr27 and Yr32 under field conditions (Fig. 2). Also, collected samples from barley and wheat were sent to Global Rust Reference Center (GRRC) in Denmark to identify this race. The uredospores and teliospores of yellow rust fungus were found to be comparable in shape and size upon light microscopic examination (Fig. 3A, B, C and D).