IPN-like materials based on polyethylene and butyl methacrylate copolymers were prepared by in situ polymerization above the melting point of PE. A co-continuous phase morphology was observed. The use of butyl methacrylate-co-methyl methacrylate and a low content of methacrylate crosslinker resulted in a fine dispersion of the IPN components in one another. Grafting reactions during the synthesis of the IPN-Iike materials between PE and methacrylates were demonstrated. A decrease in the chain length of the substituent at the ester group of the methacrylate comonomer, in the order dodecyl methacrylate (DMA) > 2-ethylhexyl methacrylate (EHMA) > butyl methacrylate (BMA), is advantageous to the mechanical properties of the IPNs.