The use of magnesium hydroxide was investigated as a flame retardant in the cable insulation material that has low density polyethylene cross-linked by silane grafting method. The different insulation samples with low density polyethylene tilled magnesium hydroxide were prepared and physical and mechanical properties of these samples were measured such as tensile strength, elongation at break, impact, bending, oxygen index, smoke density, flammability, ageing test, hot set test, ozone resistant, according to standard test methods. The test results were analyzed to determine suitable magnesium hydroxide ratio for the cable insulation material. The magnesium hydroxide ratios were found to give good material properties which will meet insulation standard. (C) 2007 Elsevier Ltd. All rights reserved.