Enterococcus faecalis is associated with different root canal infections ,and it is the main cause of chronic periapical lesions . Furthermore it is difficult to eliminate it from root canal in one visit or more ,so The aim of this study was to evaluate the antimicrobial activity of root canal paste on E. faecalis. 42 extracted single rooted primary teeth were manually prepared, sterilized, and then infected with clinical isolates of E. faecalis for 30 days. bacteria were exposed to ZOE and Ledermix pastes as intracanal medication for 1 week. Finally bacterial samples were collected, and colony-forming units were enumerated. none of pastes resulted in complete elimination of bacteria. The antimicrobial effect of ZOE was significantly better than Ledermix at P=.05 . this study has shown that none of the sealers totally inhibited the growth of E. faecalis , and ZOE paste had the greater reduction of the CFU count for E. faecalis cells than Ledermix