The melting temperature of polyethylene crystals decreases and the lattice constants (bothaandb) and lattice distortion increase, but the macroscopic volume of the specimen does not change with electron irradiation. From these results a model of a deformed lattice structure with point defects produced by irradiation is proposed. Calculations indicate that the anisotropy of a polymer crystal (difference between the elastic modulus along the molecular axis and perpendicular to the axis) increases the range of the distortion in a crystal caused by a defect. The presence of lattice distortion in electron irradiated polymer single crystals produces observable features in the Moire´ patterns obtained from the crystals.