Introduction: Effective endodontic  treatment requires identification of all root canals. The inability of dentists to locate all root canals can lead to the failure in endodontic treatment. Consequently, an accurate diagnostic device is essential to detect all root canals .  The aim of this study was to examine the accuracy of cone- beam computed tomography(CBCT) as a diagnostic tool to detect  the root canals of  maxillary first premolars in a selected Iranian population.
Materials & Methods: In this in vitro study,48 human extracted maxillary first premolar teeth were scanned by CBCT, and then all teeth were sectioned. In  the current study, sectional method was chosen as the gold standard. The  CBCT scans were observed by an oral and maxillofacial radiologist, and the sections were evaluated by an endodontist using stereomicroscope. Finally, the collected data were entered into SPSS-22 and analyzed by Kappa coefficient and Chi-square test. Significance level was set at 0.05.
Results: The agreement between CBCT and sectional methods for root canal detection was 97.2% which was significant (95.8% in the first section, 97.9% in the second and third sections), (p<0.001). 
Conclusion: It seems that CBCT is a safe and non-invasive tool that can be used to detect root canals if other low-dose radiation imaging techniques do not provide acceptable results.