Aluminium titanate was strengthened by alloying with 3 mol% yttria stabilized zirconia to attain a small expansion coefficient of 2 x 10(-6) and a high strength of 100 MPa, simultaneously. Long milling and optimization of the composition of the alloy to an equal weight of the component oxides and also of the firing temperature at 1400 degrees C were important for the purpose. In the optimal conditions, aluminum titanate grains of 3 mu m was surrounded by zirconia matrix of ca. 0.3 mu m grains containing zirconium titanate where would be a balance between the tension in the matrix and the expansion force of aluminum titanate grains. Formation of zirconium titanate was important for the strengthening to decrease the lowering of the strength brought about by the unstabilization of PSZ.