Using the zone method of a linear combination of plane waves for the supercell model, there have been studied energy and electron states of beryllium monoxide BeO with intrinsic point defects: the vacancy in the sub-lattice of beryllium + interstitial atom of Be {VBe + Bei}. The most stable among the considered configurations of defects are the vacancies and interstitial atoms of beryllium Be i o occupying octahedral positions at R(VBe-Be i o ) ∼ 3.15-3.35 Å distances from each other. Depending on the configuration of defects, the forbidden gap of beryllium oxide can change by ∼0.4-2.4eV. © 2006 Springer Science+Business Media, Inc.