Aim: The aim of this in vitro study was to evaluate the antimicrobial effectiveness of four endodontic sealers (AH Plus, Enseal, MTA fillapex and Sealapex) after 48 hours. Materials and Method: The freshly mixed sealers used were AH Plus, Enseal, MTA fillapex and Sealapex. The sealers were prepared according to manufacturer’s instruction and placed in prepared wells of 36 agar plates which were inoculated with Streptococcus viridans, Staphylococcus aureus and Enterococcus faecalis. (10 samples were made for each Microorganisms). Four cavities, each one measuring 5 ml in diameter and 4 ml in depth were made in each agar plate using cork poorer. Agar diffusion method on Muller Hinton agar was employed and zones of inhibition were measured after 2 day. Results: Sealapex proved to be the most effective against all microorganisms tested. This was followed by Enseal. AH Plus showed antibacterial activity on all tested microorganisms slightly higher than that of MTA fillapex which showed the least action on all tested microorganisms. Conclusion: All the sealers evaluated in this study showed different inhibitory effect