  We present the results of a new calculation for the photodisintegration of
ultra-high energy cosmic ray nuclei on soft photon targets. We include all the
relevant photodisintegraton processes i.e giant dipole resonance,
quasi-deuteron, baryonic resonances and photofragmentation. In particular, for
the giant dipole process we use a recent calculation of the giant dipole cross
section. We calculate the mean free path for photodisintegration processes for
radiation fields that are likely to exist within galaxies and clusters of
galaxies.
