The effect of incorporation of the two different fillers, i.e. calcium carbonate and magnesium hydroxide, over a concentration range of 0-35% w/w on mechanical and burning properties and hot set test of polyethylene (PE) has been studied. The incorporation of either of these fillers deteriorates mechanical properties such as percent elongation at break and tensile strength of PE. However, modification of PE not only mitigates the reduction in these properties, but brings enhancement in all the aforementioned properties. A clear difference in these properties for the incorporation of each of these fillers to just PE, silane-grafted but uncured PE, and silane cross-linked PE has been found. These properties follow the order of superiority as: crosslinked PE > silane-grafted uncured PE > physically filled PE. The different properties due to physical bonding of filler, physical bonding in the presence of polar silane grafted onto PE, and that of chemical bonding of filler in cross-linked PE has been discussed and analyzed. (c) 2005 Wiley Periodicals, Inc.