The aim of this study was to compare some properties (total shrinkage, bending strength, apparent porosity and thermal shock resistance) of porous alumina-mullite ceramics depending from the type and the initial grain size of mullite precursor. As mullite precursors were used silica (SiO2), silicon carbide (SiC) and silicon nitride (Si3N4) powders. Mullite forms in high temperature reaction of alumina (Al2O3) and SiO2. SiC and Si3N4 particles during sintering oxidize into SiO2 and also form mullite in the reaction with alumina. Compositions in all series were calculated to obtain equal theoretical amount of SiO2 (3.6 wt.% and 7.3 wt.%) after oxidation of precursor. Samples were produced by slip casting method. Pores in these materials form in the result of chemical reaction of aluminium with water in alkaline medium (pH≥8). The samples were fired at two different temperatures – 1650° and 1750°C. The bulk density of investigated materials is in the range from 0.95 to 1.26 g/cm3. Apparent porosity is in the range from 58% to 64%. Bending strength is in the range from 2 to 11 MPa.