Kirchhoff modes in an

network are defined as the class of complex current (voltage) distributions satisfying only the pertinent Kirchhoff law. A sufficient number of such modes forms a complete set in the sense that each permissible current (voltage) distribution can be represented as a linear combination of these modes. If the basic set of modes satisfies certain properly defined orthogonality and normalization properties, the response of the network to a given distribution of sources can be immediately determined by means of Tellegen\´s theorem. An extension of Kirchhoff mode theory to a wider class of networks is indicated.