AlN plates were fabricated by hot pressing at $1700-1900^{circ}C$ using yttria and alumina (3 and $10;{mu}m$ particle size) powders as additives and characterized: density, thermal conductivity, transverse rupture strength, and grain size measurement by SEM and EDS. Density values of $3.31-3.34;g/cm^3$ are largely attributed to hot pressing of powder mixtures in carbon mold under $N_2$ atmosphere which caused effective degree of oxygen removal from yttrium-aluminate phase expected to form at $1100^{circ}C$. The grain size of hot pressed AlN was almost homogeneous, with size approximately from 3.2 to $4.0;{mu}m$ after hot pressing. $Al_2O_3$ powder of $3;{mu}m$ particle size resulted in better transverse rupture strength and finer grain size compared to $10;{mu}m$ $Al_2O_3$ powder. The thermal conductivity of AlN ranged between $83-92.7;W/m{cdot}K$ and decreased with $Al_2O_3$ addition. Fine grain size is preferred for better mechanical properties and thermal conductivity.