The purpose of the present study is to determine the effect of wheat yellow rust caused by Puccinia striiformis f. sp < em>. tritici on quantitative and qualitative grain yield losses, in addition to predict them through regression model for each tested wheat variety, i.e., Shandweel-1, Gemmeiza-11, Sids-1, Sids-12, Sakha-94 and check variety Morocco in 2020 and 2021seasons at Bahteem Agricultural Research Station, Agricultural Research Center, Egypt. The disease parameters i.e., final rust severity (FRS %), rate of yellow rust increase (r-value) and area under disease progression curve (AUDPC) in the first season were higher than the second season. Gemmeiza-11 and Sids-12 varieties recorded the highest values of these parameters during the two seasons compared to the check variety Morocco. Corresponding data ranged from 63.33 to 83.33% for FRS (%) 0.043 to 0.063 for r-value and 783.33 to 1350.0 for AUDPC. Shandweel-1 and Sids-1 varieties recorded the moderately values of these parameters but Sakha-94 recorded the lowest values of the same parameters. The actual losses (%) values, ranged from 1.31 to 36.44% for 1000 kernel weight/gm and grain yield/plot (kg), were lower than the total losses (%) which ranged from 1.38 to 42.94%, respectively, for each of wheat varieties in the two seasons under study. The highly susceptible wheat varieties, Sids-12 and Gemmeiza-11 exhibited the highest values of actual losses (%) and total losses (%) up to 42.94%, while the moderately susceptible varieties, Shandweel-1 and Sids-1 were less, being 21.05% compared to the check variety Morocco. In addition, Sakha-94 variety showed less than 3.37%. The regression analysis showed that a positive strong correlation between FRS and total losses (%) of 1000 kernel weight/gm and grain yield/plot (kg), during the two growing seasons. The qualitative properties of wheat varieties revealed that the reduction rates for carbohydrate mg/g, total protein mg/g, crude fiber, dry gluten and wet gluten were higher in the susceptible wheat varieties, Shandweel-1, Gemmeiza-11, Sids-12 and Morocco (check), where the corresponding values ranged from 3.80 to 33.07%, while Sakha-94 and Sids-1 showed the lowest reduction from 1.30 to 9.6%, in the tested chemical properties. So, through this study, it can expect the yield loss by linking disease parameters, yield components and chemical properties. Principal component analysis showed that the most important components were FRS (%) and AUDPC, as they contributed 88.607% of the total cumulative variance and a prediction equation may link all the components together.