The satellite structure of the Cls and Ols photoelectron spectra of chromium hexacarbonyl Cr(CO)(6) has been calculated by the INDO/CI method and compared with available high resolution core level photoelectron spectra. A reassignment of some of the lines is made. It is found that the satellite structure in both cases is dominated by excitations from metal-ligand bonding to metal-ligand antibonding Me(3d)-pi* orbitals, and that these shake-up excitations involve a significant charge transfer to the core ionized ligand from the rest of the molecule.