Hayam Y. Hassan ¹, Ahmed M. Negm², Marwa M. Azab³, Elham I. Elshaboury ^{4           1} Assistant Professor of Endodontic, Faculty of Dentistry, Suez Canal University, Ismailia, Egypt. ² Assistant Professor of Endodontic, Faculty of Dentistry, Ahram Canadian University, Giza, Egypt. ³ Assistant Professor of Microbiology & Immunology, Faculty of Pharmacy, Suez Canal University, Ismailia, Egypt. ⁴Associated Professor of Endodontic, Faculty of Dentistry, October University for Modern Sciences and Arts (MSA), Giza, Egypt. Abstract: Aim:evaluation of the antibacterial efficacy of calcium hydroxide mixed with Biopure MTAD, propylene glycol and distilled water against Enterococcus faecalis. Methods:55extracted teeth were selected, prepared and sterilized. Five teeth were cultured (negative control group). Others were infected by a Trypticase Soy Broth suspended with E. faecalis. Infected roots incubated at 37^oC for 48 hours. Then five teeth cultured without treatment (positive control group). While, the residual were distributed into three groups (n=15), group 1 (Biopure MTAD+ calcium hydroxide), group 2 (propylene glycol+calcium hydroxide) and group 3 (distilled water+calcium hydroxide). The medication mixed in 1:2 ratio and applied into the root canal of each corresponding first, second and third groups. Assessment of bacterial efficacy verified at three intervals 7, 14 and 21 days by swabbing and cultured on M-EnterococcusAgar plates. After incubation for 24 hours, the total count of colony-forming units per milliliter (CFU/ml) were recorded. The data were collected tabulated and subjected to statistical analysis. Results:the highest antimicrobial efficacy recorded by group 1 followed by group 2 then group 3. Conclusions: mixingcalcium hydroxide with both Biopure MTAD and propylene glycol improved the antimicrobial efficiency of it against E. faecalis.