The root end filling materials antibacterial properties is a must nowadays as there is none of the available root canal filling materials can provide a hermetic seal.The aim of the current study isto compare the antibacterial effect of Gray Portland cement and white MTA angelus in the conventional and nano-particle forms. Agar diffusion test was used to examine the tested materials, where Enterococcus faecalis ATCC29212 (American Type Culture Collection 29212) cultured in agar BHI (brain heart infusion) in anaerobic condition at 37oCfor 72 hours.Then, the agar was added to 12 sterile petri plates and the prepared bacterial suspension was inoculated. Punch holes of 6 mm diameter were formed on each agar plate and each 3 plates were filled with the materials tested (Portland cement, Nano-Portland cement, MTA angelus, and Nano-MTA angelus). The results showed that conventional Portland cement has the highest antibacterial property, followed by Nano-Portland cement, MTA angelus, Nano-MTA angelus respectively with significant difference according to Kruskal Wallis ANOVA test followed by Mann-Whitney U test.