Yellow rust biological trap nurseries were planted in different locations representing the main wheat growing areas in Iraq. The plants were exposed to the natural population inoculum of the pathogen in the fields. Diseases scoring were conducted by recording disease severity and infection types on each genotype at different stages of wheat development. Yellow samples collected from the commercial wheat fields from different locations were sent to the Global Rust Center for race analyses. Virulence analysis of Puccinia striiformis f. sp. tritici population, revealed virulence detection against the known resistant genes Yr2, Yr6, Yr7, Yr9, Yr18, YrA, Yr20, Yr21, Yr27, Yr28, Yr29 and Yr31at adult plant stage in Sulaimania, while virulence against the known resistant genesYr2, Yr6, Yr7, Yr9,Yr SD, YrSP,YrA, Yr21, Yr27, Yr28 andYr31, were detected in the natural populations of P. striiformis f. sp. tritici at adult plant stage Nineveh. Virulences were also detected against the known resistant genes Yr5, Yr6, Yr7, Yr9,Yr20, Yr21, Yr27, Yr28 and Yr31in Babylon and against Yr2, Yr5, Yr6, Yr7, Yr9, Yr18, YrA, Yr20, Yr25, Yr28, Yr29 and Yr31in Diyala. Out of 21Yr samples sent to GRRC for race analysis, 10 samples were recovered while 11 samples were failed to be recovered. Two pathotypes (races) were prevalent in P. striiformis f. sp. tritici population, the first one had virulence against Yr2, Yr6, Yr7, Yr8, Yr9, Yr27 and AvS while the second one had virulence against Yr2, Yr6, Yr7, Yr8, Yr9, Yr25, Yr27 and AvS at seedling stage.