We have proposed an approach to use a gamma-ray for nuclear transmutation by Compton scattering of laser photons with high current accelerator. We demonstrated laser Compton scattering to obtain 20 MeV gamma-ray to address transmutation rates with the giant resonance of Au-197 and (121)Iodine. Experiments for measurements of neutron spectrum and pair production were performed for energy balance of this scheme and for target conditions. The results showed reaction rate was about 2-4% for appropriate photon energies and neutron energy was up to 4 MeV in the calculation. (C) 2007 Elsevier Ltd. All rights reserved.