Retreatment is an attempt to re-establish healthy periapical tissues after inefficient treatment or reinfection of an obturated canal because of coronal or apical leakage. Aim: To compare the efficacy of R-Endo, Mtwo retreatment and Protaper D Files for the removal of gutta precha using cone beam computed tomography and stereomicroscope. Methodology: 60 mandibular premolars were obturated using Calamus 3D Obturating system. Gutta percha was removed using the three rotary retreatment files. Amount of gutta percha left was evaluated using cone beam computed tomography and stereomicroscope. Result: R Endo removed more gutta percha in the middle and apical third where as Mtwo files in the cervical third. Protaper D Removed the least amounf of gutta percha at all levels. Conclusion: R Endo retreatment file proved to be the most efficient system then MTwo and Protaper D Files. Schlagwörter: retreatment, calamus, two retreatment file, protaper, endo