Investigation of fabrication of α-sialon and α-/β-sialon ceramics from nanopowders by hot pressing (1800 and 1910 °C) were carried out. Samples of sialons were made by using Si 3 N 4 -AlN nanopowders composites fabricated by the method of plasmachemical synthesis. The hardness of materials from nanopowders are of HV 1 = 17,6-21,9 GPa, bending strength of σ 3p = 520-800 MPa and fracture toughness up to K lc = 7,1 MPa.m 1/2 , depending on composition and compacting temperature.