A new formulation of the conductor-like polarizable continuum model is presented, to extend this approach to infinite periodic systems. Solutes with one-dimensional (polymers) and two-dimensional (surfaces) periodicity can be described. The procedure is based on a reformulation of the Coulomb sum, expressing the mutual interaction between the apparent solvation charges, that allows one to separate the contribution of each solvation charge; the reliability of such formulation has been tested on some simple model systems. (C) 2003 Elsevier B.V. All rights reserved.