Purpose: The aim of this study was to evaluate canal transportation and centering ability ratio of 2 single Ni-Ti instruments; one shape and wave one gold using Cone Beam Computed Tomography scanning (CBCTs). Materials and Methods: Forty mesiobuccal canals of human mandibular first molars with a curvature angle that ranges from 15° to 35° were divided into 2 groups based on the type of instrument used to prepare the canal. Group I: instrumented with one shape and Group II: instrumented with Wave One Gold. Pre and post preparation, canals were scanned using CBCT scanner to evaluate the amount of canal transportation and centering ability ratio at coronal, middle, and apical parts of root canal system. Results: There was no statistical significance difference between the two tested groups (P<0.05) in canal transportation and centering ability. Conclusion: Both one shape and wave one gold systems preserving the canal's original form.