Fluorescent in situ hybridization (FISH) and sequential C-banding and FISH techniques were used in locating 45S rDNA sequence on specific chromosomes of Triticum monococcum, T. dicoccoides, T. aestivum, Hordeum vulgare, Haynaldia villosa, T. durum-Haynaldia villosa amphiploid, Avena fatus, and Roegneria kamoji. High polymorphism between common wheat and its relatives on 45S rDNA sequence distribution was detected. All the chromosomal secondary constriction regions of these species had 45S rDNA loci. Some non-satellite chromosomes had additional 45S rDNA loci. A 45S rDNA locus was located on the terminal region of the short arm of R. kamoji chromosome 1Rk#1.