Hardness, toughness, wear resistance and bending strength of the alumina based ceramics, irradiated with gamma rays (0.8 MeV) doses of up to 2000 Mrad were investigated. It was found that the mechanical properties of the ceramics, where corundum prevails, degrade with the increase of the irradiation dose. The most resistant to gamma irradiation was ceramics, consisting of an equal volume fractions of Al 2O 3 and 2.5YSZ. Different trend of the corundum crystal structure period change with an increase of irradiation dose was found: crystal volume increases in ceramics with zirconia (ZTA10 and ATZ50), and reduces in ceramics free from zirconia (Al 2O 3 and AM1) when increasing the irradiation dose.