The recombination current in grain boundaries is theoretically investigated for a polycrystalline silicon solar cell n-p junction operating either in short-circuit or in open-circuit configurations. The analysis is carried out using results performed in earlier works, by means of numerical simulations including the presence of grain boundaries. The variation of grain boundary recombination current density with exciting light wavelength is reported for different cell parameters like grain boundary recombination velocity, base dopant density and base thickness. The objective of the present paper is to understand to what extend the light wavelength and the junction configuration allow an optimal measure of the grain boundary recombination parameter. (C) 2003 Elsevier B.V. All rights reserved.