Introduction: in endodontic therapy, chelating agents appear as auxiliary products during the root canal shaping process, lubricating and assisting in smear layer removal. The aim of this study was to compare the efficacy of three chelating agents (RC-Prep, Glyde and Kelfar) in removing smear layer in 40 healthy, single-rooted premolars. Methods: access cavities were opened in 40 single-rooted teeth in order to subsequently clean and shape each root canal. The sample was divided into four groups: Group 1 consisted of teeth prepared with RC-Prep; Group 2 of teeth prepared with Glyde; Group 3 of teeth prepared with Kelfar; and Group 4 was a control group. The teeth were irrigated between files with 2 ml of sodium hypochlorite at 5.25%. Later the teeth were dried with paper points and were cut lengthwise to be SEM (Scanning Electron Microscope) observed. Results: no statistically significant difference was found, except in the apical third of the teeth treated with Glyde. Conclusions: Glyde displayed better behavior compared to RC-Prep and Kelfar. Although there was no statistically significant difference, it is important to use a liquid chelating agent to improve smear layer removal.