Aim of the study was to evaluate the canal transportation and centering ability of three nickel-titanium single file rotary systems by cone beam computed tomography (CBCT). Materials and methods: Thirty permanent maxillary first molar with a range of mesiobuccal canals curvature from 20-30 degree were selected and assigned into three groups (n=10), according to the biomechanical preparation system used: Hyflex EDM (HF), Reciproc blue (RB) and OneShape (OS). The sampled were scanned by CBCT after being mounted on customized acrylic base and then rescanned after the instrumentation. Slices from the axial section were taken from both exposures at 3 mm, 6 mm and 9 mm from the root apex corresponding to the apical, middle, and coronal third respectively. Data were statistically analyzed using Kurskal-Wallis and Mann-Whitney U tests at the 5% confidence level. Results: The results showed that there were no significant differences at the apical and coronal third and a significant difference at the middle third regarding canal transportation. However, there was a significant difference at the apical third and no significant difference at the middle and coronal third regarding centering ratio. Conclusion: It was concluded that the three single rotary systems reported a degree in canal transportation and centric ratio but the Hyflex EDM reported the least one.