Background: To achive success in endodontic treatment, the clinicians have to completely control the depth of penetration of instruments inside the root canal called the working length. Determining the working length by using electronic apex loactors have been increasingly popular and gradually become an indispensable tool in endodontics. The purposes of this study was to compare the working length determined by Propex Pixi with the actual canal length as well as evaluate the effect of various intracanal irrigants on the accuracy of Propex Pixi. Materials and method: 45 human incisors extracted for periodontal reasons were selected for this in vitro study. Standard access preprations were prepared, then digital Caliper was used to meassure the actual root canal length. Teeth were imbedded in alginate model. The working length was determined by using the Propex Pixi in the presence of different irrigant solutions: distilled water, 2.5% NaOCl and 2% Chlorhexidine. The working length meassurements obtained with Propex Pixi were compaired with the actual root canal length and then evaluating the effect of irrigation solutions on the accuracy of Propex Pixi. Results: There was no significant differences between the actual canal length and the WL determined by Propex Pixi (p > 0.05). Root canal irrigants has no effect on the accuracy of Propex Pixi. Conclusion: There was no significant differences between actual root canal length with the measurements obtained by Propex Pixi. The accuracy of Propex Pixi was not affected by the irrigants used. Key words: working length, electronic apex locator, Propex Pixi.