In this work, changes caused by gamma-radiation on binary blends of different PEs (high, low and linear low-density polyethylenes) with PA6 were studied. The structure and property changes in these samples induced by gamma-irradiation were characterized by the ESR, DSC and FTIR techniques. These techniques provide relevant information concerning the reaction mechanisms of the structural modifications that take place during the irradiation of polymers. The experimental results suggest that allyl, alkyl and polyenyl radicals are generated in the materials by the irradiation process. The dynamics dominating the process kinetics seem to be crosslinking, chain scission and a coexistence of both, depending on the sample composition and the absorbed dose. The degradation of the materials produced a disruption in the ethylene sequences in polyethylenes thus decreasing their melting point. Bands attributed to carbonyl groups (C=O) were observed in FTIR spectra after the materials were irradiated.