The effect of electron beam irradiation, followed by chemical treatment, on the macromolecular structure and crosslinking parameters in low density polyethylene (LDPE) films has been studied through scanning electron microscopy (SEM). The electron beam irradiation with low doses increases the co-operation of the sublevels of the superstructural molecular organization, due to the radiation-induced crosslinking of the macromolecular chains in the intercrystaUine amorphous regions, changes the microrelief weakly, but does not change the type of the microdestruction mechanisms. At irradiation with D = 25 Mrad, the type of the microdestruction is changed from plastic to brittle due to the high values of the density of the spatial crosslinking (Vc) leading to suppression of the micro-Brownian macromolecular mobility. The chemical treatment of the samples, after the irradiation, leads to a transition from plastic to brittle type microdestruction mechanisms even at low irradiation doses. At higher irradiation doses, the macromolecular structure of the samples contains groups of chain folded crystalline lamellae which are arranged into large packages. This is due to the creation of macromolecular networks with included in them mutually penetrating lattices. Each lattice has its own spatial crosslinking density, which differs considerably from the crosslinking densities of the other lattices.