Nearly stoichiometric and Ga-rich CuGaSe2 films for photovoltaics were investigated by contactless and non-invasive transient photoconductance measurements in the microwave frequency range. The stoichiometric material is characterized by a fast first order recombination process at low excitation densities that is quenched in the Ga-rich material. In the Ga-rich material excess charge carrier kinetics is characterized by an extended decay over several orders of magnitude in time. This leads to a much longer average lifetime in the Ga-rich material, which may help explaining the higher efficiency of this material in solar cells. The higher effective mobility in stoichiometric CuGaSe2 has only a minor influence. (C) 2003 Elsevier B.V. All rights reserved.