Background and Objectives: To evaluate and compare the apical sealing ability of three different root canal sealers Bioroot RC (tricalcium silicate-based sealer), Nanoseal S (polydimethylsiloxane-based sealer) and Eposeal (epoxy resin-based sealer) by dye penetration method under a stereomicroscope. Method: Three commercially available endodontic sealers were used in this study: Bioroot RCS (Tricalcium silicate-based sealer), Nanoseal S (Polydimethylsiloxane based sealer), Eposeal (Epoxy resin-based sealer), were used to assess the sealing ability in the apical area of the single rooted permanent teeth by dye penetration method under a 30x stereomicroscope. Teeth were obturated with the sealers and gutta-percha and stored in humidifier for 1 week, centrifuged with 2% methylene blue dye and ground sections were examined under a stereomicroscope. The results were obtained by measuring the dye penetration in the apical area under stereomicroscope. Results: Eposeal (Epoxy resin-based sealer), showed the least dye penetration producing a mean dye penetration of 0.8000mm. Nanoseal S (Polydimethylsiloxane based sealer) showed the highest dye penetration with the mean of 1.5000mm. Bioroot RC (calcium silicate-based sealer) showed the moderate dye penetration of with the mean of 0.8500mm. Conclusion: On the basis of the results of the present study, it can be concluded that all the sealers demonstrated dye penetration with differences according to the material used. Furthermore, Eposeal (Epoxy resin-based sealer) showed the least dye penetration among the three sealers tested, followed by Bioroot RC and Nanoseal S sealer.