Stripe rust, caused by Puccinia striifarmis f. sp. tritici is an dangerous disease of wheat worldwide. To estimate grain yield losses due to stripe rust, replicated experiments including forty wheat genotypes i.e. Gemmeiza 9, Gemmeiza 11, Sakha 61, Sakha 69, Sakha 93, Sakha 94, Sids 12, Sids 13, Misr 1, Misr 2, Giza 168, Giza 171, Shandweel 1 and Morocco were evaluated for adult plant resistance at Sakha Research Station, Kafr El-Sheikh, Egypt during 2013/14 and 2014/15 growing seasons. The field experiment was surrounded by spreader area of highly susceptible genotypes i.e. Triticum spelta saharences inoculated with a mixture of stripe rust races as a source of inoculum. In general, the rust severity of wheat genotypes was higher at second season than that at first season. Disease severity was recorded each 10 days (5MR to 80S) the first season (10MR to 90S) the second season. Area under disease progress curve (AUDPC) was estimated and ranged from26 to 1750 in 2013/14 and 26 to 2050 in 2014/15. It was found that, yield losses ranged between 3.86 % in the wheat genotypes Shandaweel 1 to 31.17 % in the wheat genotypes Morocco during 2013/14, while during 2014/15 ranged from 3.86 % in the wheat cultivar Misr 2 to 37.39 % in the wheat cultivar Morocco. Concerning yield losses in 1000-kernel weight, the genotype Sakha 61 recording less value 2.6 % white Morocco was higher value 30.49 % and 32.74 % in two growing seasons. High correlation was found between yield losses with disease severity and AUDPC.