Sintering of materials with a bimodal porous structure under conditions of external kinematic limitations that make their macroscopic deformation impossible is considered. It is established that in contrast to materials that contain pores of the same size, with sintering of materials that have a bimodal pore distribution under the conditions indicated above there is deformation within the limits of the matrix material. It is demonstrated that a monomodal pore structure under the same conditions is not stable, in the sense that small disturbance of the uniform pore distribution with respect to size may lead to marked stratification during sintering. Tangential stresses that arise in the solid phase as a result of the existence of two types of pores are evaluated.