Introduction:This study was aimed to evaluate the efficacy of 17% ethylenediaminetetraacetate (EDTA), 7% maleic acid and 0.7% fumaric acid in smear layer removal from the root canal walls.Materials and Methods:Forty single-rooted mandibular premolars were collected and prepared till F3 rotary ProTaper file with 1 ml of 3% of sodium hypochlorite after each instrument change. Samples were randomly divided into 4 groups according to the final irrigating solution: 17% EDTA, 7% maleic acid, 0.7% fumaric acid, and 0.9% saline. The samples were prepared for scanning electron microscope analysis to observe smear layer removal at coronal, middle, and apical third level of root canal system.Results:At coronal third level, fumaric acid was equally efficient in smear layer removal when compared to maleic acid and EDTA without any significant difference between them. At the middle third, fumaric acid showed significantly better results than maleic acid followed by EDTA. At the apical third, both fumaric acid and maleic acid were equally effective without any significant difference between them but both showed significantly better results than EDTA.Conclusion:Fumaric acid can be tried as a new irrigating agent for smear layer removal in root canal system.