A new LTCC (low-temperature cofired ceramic) system containing Al2O3 platelets instead of conventional Al2O3 particles as a filler material was investigated. As the Al2O3 platelets were arranged parallel to the casting direction during tape casting and had preferred orientation in the green tape, the linear shrinkage of the green body took place mainly in the direction perpendicular to the platelet planes with just a little shrinkage in the horizontal without any external force during sintering. The intended anisotropic shrinkage of the new LTCC system made the constrained sintering of 10-mm-thick ceramic body possible, which decreased the sintering shrinkage tolerance in the xy directions of the 10-mm-thick ceramic body from 0.5% to 0.05%. The new LTCC system showed equivalent electrical properties and remarkable physical properties in comparison with a conventional LTCC system.