In order to identify the alien chromosome introgressed into the wheat's genome of the aneuploid lines of the cross: Triticum aestivum cv Kiten (AABBDD) x Aegilops kotschyi (UUSS) a protein polymorphism (gliadins and glutenins) as markers for 1−stand 6−thhomoeologous group is used. An SDS-PAGE and a native 1-D-slab PAGE in the case of glutenins and gliagins respectively are performed. Some additional bands specific for Ae.kotschyi as well as a comparison to Ae. umbellulata (UU), Ae. longissima (S1S1), Ae. squrrosa (DD) and Chinese Spring nullitetrasomic lines indicate the introgression of U genome in the investigated disomic addition and substitution lines. The results of this study show that the polymorphism of the storage proteins can be used as a reliable marker system for quick and cheaper screening of the presence of alien chromosomes.