The stress required for complete constrained sintering of a low-temperature cofirable ceramic-filled glass composite, i.e., borosilicate glass + alumina, has been investigated under uniaxial constant and cyclic loading. The required uniaxial stress to have complete constrained sintering, i.e., zero strain or strain rate in the perpendicular directions, is in the range of 20-250 kPa, which initially increases with temperature, reaches a maximum at 725degrees-800degreesC, and then decreases with increasing temperature. The above measured data exhibit a similar trend to those of required stress and sintering potential calculated using the viscous analogy for the constitutive relationship of a porous sintering compact.