During 2012-2013 growing season, symptoms of stem rust disease on the stem, leaf sheath and spike of barley (Hordeum vulgare L.) were observed on C.C. 89 / 3/ Alanda / Lignee 527/ Arar line which its pedigree is Egsk 03 / 04 / No. 1199-4-1-2. These symptoms were detected on this line at Nubariya Experiment Research Station, Behera Governorate, Egypt. Uredial and telitial pustules on barley's stem, leaf sheath and spike were observed (Fig.1). Isolation was carried out from single pustules, multiplied and the resulted spores were used to carry out pathogenicity test on the same line. Typical symptoms of Puccinia graminis Pers. f.sp. tritici Eriks and Henn. (Pgt) were obtained after 14 days and were similar to those previously observed on the collected infected barley samples. Also, ordinary microscope photographs showed the presence of both uredial and telitial stem rust pustules in naturally infected samples (Fig. 2). It is worthy to mention that in 1999 in Uganda, a new highly virulent race of Pgt designated Ug99 was detected. Also, barley stem rust was reported in West Central Minnesota. Ug99 can attack all U.S. barley varieties, including those carrying the resistance gene Rpg1, which has protected barley from losses since 1940s. In Africa, different races closely related to Ug99 have already been detected and screened against 20 barley cultivars. In Egypt, significant differences in the rapidity of development of Pgt races on 50 wheat and barley varieties were recorded under greenhouse conditions. As the researchers are far aware, natural incidence of stem rust (Puccinia graminis) is recorded herein for the first time on barley (Hordeum vulgare L.) Line C.C. 89 / 3/ Alanda / Lignee 527/ Arar growing in Nubariya Res. Station. According to these facts, major efforts are required now to detect and displace current stem rust susceptible barley line with resistant ones.