Segregated grain boundaries have a different chemistry and structure than the bulk of the grains. Yttrium segregated general grain boundaries (GB) in polycrystalline α- Al 2 O 3 were investigated by electron energy loss spectrometry (EELS). Energy loss near edge structure (ELNES) spectra of Al-L and O-K edges from the segregated GBs and from the adjacent bulk alumina were experimentally obtained. Spatial difference method was applied to enhance the grain boundary features. Reference spectra from different Y-Al-O compounds, i.e. Y 3 Al 5 O 12 , YAlO 3 , and Y 4 Al 2 O 9 , as well as Y 2 O 3 and α-Al 2 O 3 were experimentally measured and theoretically calculated by the ab-initio self-consistent orthogonolized linear combinations of atomic orbitals (OLCAO) method. A comparison between the reference spectra and spatial difference spectra from the grain boundaries was used to study the local chemical and structural environment of the atoms at the segregated GBs.