Yellow rust or stripe rust is the most prevalent fungal disease in Iran and also different regions of the world. Therefore, it is necessary to study and identify the properties of different races of this fungal pathogen. For this purpose, 29 Pst isolates collected from different regions of Iran, were tested at the seedling stage using 44 differancial lines and the susceptible cultivar Bolani.. The seedlings were inoculated with the pathogenic isolates. After 17 days, notes were taken using Johnson et al method, and the races were determined. According to the results, pathogenicity was detected for the plants carrying the gene YrA all isolates. No pathogenicity was recorded for the plants carrying the genes Yr5, Yr10, Y15, and YrSP in this study. The races 132E156A,Yr27 of Ahvaz 3 and the race 2E2A of Mashhad were identified as the most and least agreesive races, respectively.