The thermodynamics of the liquid phase migration in a nanodispersed composite body has been studied. An expression describing the variation of the Gibbs potential in the course of the above process has been derived. The notion "the migration pressure" has been introduced. The equation for the migration pressure has been derived, which includes size of nanoparticles, interphase and surface tensions and the variation of the area of contact and interphase Surfaces in the course of migration. (C) 2009 Elsevier Ltd. All rights reserved.