The influence of a cross-linking agent (divinyl benzene) on new polystyrene-polyethylene, IPN-like networks was investigated by means of thermal, mechanical tests and a few microscopy observations. It was found that with increased concentration of cross-linking agent, i.e., with PS cross-linking density, Young＇s and storage moduli, measured in the molten rubbery state, increased linearly. Also the elongation and the stress at break were very sensitive to the content of cross-linking agent, mainly in the low concentration region (0 to 2%). PE and PS domains of about 1 mu m circular cross sections were observed on a smoothed surface of a PE/PS blend. Smaller and uniformly dispersed domains were observed for all the IPN-like systems. The crystallinity, measured by DSC and WAXS, and the IPN morphological features, appeared to be independent of the styrene cross-linking content, viz., the content of DVB. The overall behavior seemed to resemble that of classical simultaneous IPNs.