Objectives: To evaluate the accuracy between two different electronic apex locators in detecting the root canal perforation in the middle and apical portion during retreatment. Methods: Sixty freshly extracted mandibular premolars were taken in to this study, which were divided into three groups of twenty each. Group I: Control Group, Group II: Positive control without perforation, Group III: Negative control with perforation. In all the groups, access cavity preparation was done followed by cleaning and shaping using X smart Endomotor and Protaper Gold file system (Dentsply Maillefer, Switzerland). The specimens were prepared such that perforation was made in group III on the mesial side of the root at middle portion approximately 5mm from the apex after determining working length by direct visualization and stored for the database. All the specimens were obturated by using AH plus sealer and F3 Protaper gold gutta percha points and later stored in incubator at temperature of 37°C for 7days. After 7 days, gutta percha was removed from group III samples using gutta percha solvent (Xylene), Neo-Endo retreatment files. These teeth were mounted on Protrain Endodontic training kit (Simit Dental,Italy) and perforation were detected using apex locators Dentaport Root ZX (J,Morita) and Propex Pixi (Dentsply Maillefer, Switzerland). The apical perforation were made at a distance 2mm from apex after the middle perforation were restored by using Type II GIC by keeping the 35 K file inside the canal and apical perforations were detected and the reading were recorded and stored for the database. Statistical Analysis: The data obtained were analyzed by using descriptive statistics, ANOVA (Analysis of Variance), Paired t test through SPSS for window (version 22.0). Findings: In case of middle third perforation of the root canal Dentaport Root ZX showed accuracy of 87.