INTRODUCTION: Non-surgical endodontic treatment is the best way to re-establish sound periapical tissues after reinfection or inefficient treatment of a previously obturated teeth due to apical or coronal leakage. It requires regaining the accessibility to the root canal system by removing the initial root canal filling, more cleaning, and reobturation. THE AIM OF THE STUDY: Is to compare the cleaning productivity of the XP Endo Finisher R (XPR) and the Endo Activator (EA) after retreatment using the scanning electron microscope (SEM). MATERIAL AND METHODS: This study was performed on forty-five mesiobuccal canals of mandibular first molars. All teeth were obturated then retreated using D-Race rotary files. Teeth were haphazardly divided into three groups according to the cleaning method used: Group (1): XPR. Group (2): EA. Group (3): control group (no final cleaning). All the teeth were sectioned longitudinally and canal cleaning ability was assessed by the SEM. Data were statistically analyzed using Chi-Square and Kruskal Wallis tests. RESULTS: Significant differences in the smear layer and debris removal between both XPR and EA groups and the control group were detected (P<0.05). CONCLUSIONS:The XPR and the EA are both efficient in removing the debris and the smear layer after retreatment. Moreover, the XPR performed better than the EA. None of the investigated techniques were able to totally remove the filling material.