Porous ceramics have found a wide range of applications as filters for solid, liquid, and gas separation processes. The suitability of materials for use in these types of applications depends on the microstructure (grain size, pore size and pore volume fraction) and hence the mechanical and thermal proper-ties. In this study alumina and mullite-alumina ceramics with different levels of porosity and controlled pore sizes were fabricated. Microstructure and the mechanical properties such as elastic properties and biaxial strength were examined. Correlations between the mechanical properties and porosity were found.