Ethylene-propylene-diene terpolymer (EPDM) based thermal insulator represent efficient class of the high temperature thermal insulators due to their excellent thermal, mechanical and ablative properties. This classed insulator is often reinforced by Kevlar pulp and fumed silica. Ammonium Sulphate and antimony trioxide mixture as a flame retardant was added. Carbon black (CB) was added to enhance the elastomer ablative properties. different concentrations of CB were investigated. In this work, the effect of carbon black content on the characteristics of a selected EPDM based insulating formulation has been investigated. The tensile strength, hardness and elongation have been slightly improved. The thermal stability via thermal gravimetric analysis (TGA-DTG) and differential scanning calorimetry (DSC) also has been slightly improved. Whereas the ablation resistance has been considerably improved. the weight loss from sample containing 10 phr decreased by 28% relative to the neat specimen.