Introduction: Lasers are a very promising technology that might be employed in endodontic retreatment cases to improve root canal cleanliness after mechanical gutta percha removal. Aim of the study: To evaluate root canal cleanliness after mechanical removal of gutta percha with and without Er-Yag laser irradiation in terms of gutta percha, sealer remains, and smear layer. Materials and methods: Thirty-six single-rooted teeth were divided into three groups according to the retreatment approach. Group I: mechanical gutta percha and sealer removal. Group II: mechanical gutta percha and sealer removal, followed by Er-YAG laser and saline irrigation. Group III is the same as Group II, except with sodium hypochlorite(NaOCl) irrigation. Root canal cleanliness was evaluated using stereomicroscope, whereas smear layer was evaluated using scanning electron microscope. Results: Group I attained the largest remnant percentage, followed by Group II, while Group III had the lowest mean. Between the three groups, there was a highly significant difference in the mean remnant percentage. Regarding the open dentinal tubules area there were significant disparities between group III and the other two groups, with no significant difference in the mean percentage of open dentinal tubules between groupI and group II. Conclusion: Application of Er-YAG with NaOCl following mechanical endodontic retreatment showed the least filling material remnants after using the rotary retreatment files. Moreover, it had minimal effect on the patency of dentinal tubules. Finally, none of the used techniques were able to completely clean the canals from remnants.