Polyethylene (PE) and polystyrene (PS) samples were irradiated in air with 14.89 MeV electrons at the flux of 247 Gy min(-1) and the structural changes induced by the irradiation were characterized using UV-vis and IR spectroscopies, differential scanning calorimetry (DSC), and gel permeation chromatography (GPC) and by measuring the contact angle. It was found, in accord with previous studies, that the electron irradiation leads to oxidation of polymers and to splitting of aromatic rings in PS. The surface polarity of degraded polymers increases linearly with increasing electron fluence, the increase being much steeper for PS. No significant changes of crystallic phase or of melting temperature were observed in PE after irradiation. In PS, however, the electron irradiation results in macromolecule splitting and intensive crosslinking.