Purpose: to evaluate the apical sealing ability, of different obturating materials and root canal sealers used for root canal obturation. Material and methods: This study was carried out on 4 groups: MTA as a sole root canal filling material, ThermaFil and MTA as a root canal sealer, Laterally compacted gutta-percha and MTA as a root canal sealer and Laterally compacted gutta-percha + AH PLUS (control group). Each group contained 24 teeth and was evaluated for leakage. Results: Comparison of the dye penetration at 1 day showed that the highest dye penetration was recorded with MTA alone followed by gutta-percha + MTA. Meanwhile the least dye penetration was found in Thermafil+ MTA and gutta-percha +AH Plus respectively. At 1 week follow up similar results were reported with the highest dye penetration reported in MTA and the least dye penetration was reported with gutta-percha +AH Plus. Finally at 3 weeks results showed the highest dye penetration with MTA and the least dye penetration with gutta-percha +AH Plus. Conclusion: MTA recorded the highest leakage followed by gutta-percha + MTA. While AH Plus sealer recorded the lowest leakage.