Study aim: Was to compare the in vitro effect of Adseal sealer and Endoseal MTA sealer on the fracture resistance of endodontically treated teeth. Materials and Methods:Sixty extracted human mandibular premolars with single root were used for the study. Teeth were reduced occlusally to standardize the working length to 18 mm.the instrumentation was done by using protaper rotary files ,The teeth were distributed randomly to four groups according to type of sealer: Group I (n=20): the teeth were filled by Endoseal MTA sealer and Group II (n=20): the teeth were filled by Adseal resin-based sealer.Group I and group II further were divided into two subgroups according to use of EDTA: Subgroup (a): using EDTA (n=10) and Subgroup (b): without using EDTA (n=10). Group III(n=10): control -1 (preparedunfilled) irrigated with EDTA , Group IV(n=10): Control-2 (prepared-unfilled) without EDTA Results:The highest value of the resistance fracture test was showed in Adseal group followed by Endoseal MTA group, While the prepared-unfilled groups was the least mean resistance fracture, Therefor there is difference significatlly among all groups. Regardless use of EDTA, there was a statistical significance effect of EDTA on the fracture resistance of all tested groups except control groups. Conclusion:The type of endodontic sealer has influence effect on fracture resistance of root dentin.Epoxy resin sealers provides better fracture resistance than Endoseal MTAsealers. Irrigation with EDTA provides more fracture resistance to roots.