Endodontic sealers should have a wide antimicrobial spectrum and action time to eliminate microorganisms and to prevent future infection. The objectives of this study were to evaluate and to compare the antimicrobial properties of endodontic sealers. Agar diffusion test (ADT) was used to assess the antimicrobial properties of NanoSeal ™, AH26 ™, Tubli-Seal ™, Sealapex ™ and Roeko-Seal ® against Enterococcus faecalis, Pseudomonas aeruginosa, Streptococcus mutans, Streptococcus sobrinus and Escherichia coli in three incubation periods of 24 hours, 48 hours and 7 days. Data were analysed by using Kruskal-Wallis test and P value >0.05 was considered statistically significant of difference. All the tested endodontic sealers exhibited antimicrobial inhibitory activity towards the microorganisms extended to 7 days after manipulation but in descending fashion except for Roeko-Seal® which exhibited no antimicrobial activity. The antimicrobial inhibitory activity of the new experimental sealer NanoSeal™ was comparable to AH26™ and as good as other sealers, except for Roeko-Seal®.