Aim: The present study was conducted to compare the push-out bond strength and marginal adaptation of mineral trioxide aggregate (MTA) and Bio Aggregate (BA) as root-end filling materials at three different evaluation periods; 3 days, 2 weeks and two months.Materials and Method: A total of sixty-six extracted human maxillary incisors were used in this study.Root-end resection perpendicular to the long axis of the root was made on each tooth. The apical root dentin of the resected root-end cavities were sectioned transversely in order to obtain dentin discs. The lumens of the dentin discs were drilled using Gates Glidden burs.The sections were then divided into 2 equal experimental groups; according to the material used for root end filling; group I,white mineral trioxide aggregate (MTA) (Londrina, PR, Brasil) and group II; BioAggregate (BA) (Innovative BioCeramix, Vancouver, Canada). Each experimental group was further subdivided into 3 subgroups; according to the evaluation period (3 days, 2 weeks and 2 months). The push-out bond strength of MTA and BA to dentinal walls was evaluated using the push-out test of the universal testing machine. While the marginal adaptation was assessed using the scanning electron microscope (SEM).Results: Regarding the push-out bond strength; MTA and BA specimens examined after 2 months showed statistically significant higher push-out bond strength values. SEM examination of MTA and BA samples showed good adaptability to the dentinal walls with slight gap formation for the three evaluation periods. Gaps at the filling/tooth interface in both MTA and BA significantly decreased by time. Conclusion: MTA showed statistically significant higher mean push-out bond strength than BA for the three evaluation periods. Both materials showed acceptable results regarding the marginal adaptation. With time, both push-out bond strength and marginal adaptation of MTA and BA increased significantly.