Abstract: In the present work, a systematic study on the effect of different fillers namely; glass (f), granite, graphite, garnet, antimony trisulphide, alumina, carbon, marble, mica, sand, porcelain, bronze, tixolex-25, china clay and wollastonite on di-electric strength property of virgin PTFE and different filled PTFE composites (filler content 5-50%) were made with an idea to arrive at optimum filler content for achieving maximum properties. 5% marble filled PTFE shows the highest di-electric strength value than other filled grades and the lowest di-electric strength shown is 20% in case of graphite filled PTFE as graphite itself is a conductive material.