Aim: The aim of the study was to assess, in vitro, the antimicrobial effectiveness of conventional endodontic sealers containing chitosan nanoparticles or silver nanoparticles, on E.coli, C.albicans, E.faecalis using colony forming units. Methodolgy: Silver and Chitosan nanoparticles as well as Blast–X were synthesized. The nanoparticles were subjected to XRD analysis and incorporated into the various sealers used, namely, AH plus, ZOE, MTA fillapex and the laboratory processed Blast–X, which was used as the fourth sealer. The sealers were then mixed according to the manufacturer’s instructions and CFU count was done to assess the antibacterial efficacy of the four modified sealers aginst E.coli, E.faecalis and C.albicans. Results: From colony forming unit count it was observed that, by combinations of Blast+Chitosan, ZOE+Chitosan, ZOE+Silver and MTA+Chitosan there was complete inhibition of Candida albicans, while the specimens treated with Blast+Silver showed least reduction. The combination of MTA+Silver and ZOE+Silver showed complete eradication E.coli, while AH+Silver and Blast+Chitosan showed least reduction. The combinations of Blast+Silver, ZOE+Chitosan, ZOE+Silver and MTA+Chitosan showed complete eradication of E.faecalis, while MTA+Silver showed the least reduction. Statistical analysis was performed using Kolmogorov–Smirnov and Kruskal Wallis tests and a p value <0.05 was considered statistically significant. Conclusion: The incorporation of various nanoparticles into sealers or root filling materials significantly improved the antibacterial efficacy by inhibition of bacterial biofilm formation on the surface