The structure of macromolecules inside pores at the critical adsorption point (the point of exclusion-adsorption transition) is studied. The critical adsorption point is of importance in the liquid chromatography of polymers: chromatography under these special conditions represents an intermediate mode between size-exclusion and adsorption modes. The specific feature of this mode is the independence of elution volume on the molecular weight of the polymer (the distribution coefficient being unity for any molecular and pore sizes). The polymer segment concentration distributions for various distances of a macromolecule from the pore walls are calculated at the critical adsorption point. A simple picture of a polymer molecule inside a pore at the point of exclusion-adsorption transition is presented, based on the Debye-Bueche model. (C) 1997 Elsevier Science Ltd.