The effects of gamma-radiation under vacuum on linear low density polyethylene/polymide-6 blends are studied and the results are compared with the effects of the same ageing treatment on the pure polymers. In particular, solubility and melt viscosity tests were performed and data are related to the crystallization behaviour of this system. The results indicate that molecular modifications of the blends can be interpreted by considering both the effect of gamma radiation on the two polymers and the presence of some interactions between the components due to radiation processing and mixing. For the thermal behaviour, the effects of irradiation on the maximum temperature rate and enthalpy of crystallization are observed and, in general, these are more marked for the minor component at high dose.