The results on the effect of nanostructured β-sialon precursor on the sintering and properties of the resultant ceramics are presented. The standard mixture of β-sialon precursor with 0.4z substitution degree was activated for 30 min in a planetary mill with an acceleration of 28g. Activation in the planetary mill resulted in diminution of the crystallite size and significant imperfection of the crystal lattice of the powder particles. The sintering experiments were performed at 1450-1600 °C in a powder bed. The relative density of the sintered bodies achieved the value of 97 %. The nanostructured material was produced after pressureless sintering at 1500 °C. It is concluded that high activation degree of the powders is necessary to obtain fully dense ceramics.