The aim of this study was to relate the position of the cementodentinal junction (CDJ) and histologically evaluate the accuracy of three different working length determination methods. Sixty mandibular premolar teeth scheduled for therapeutic extraction were selected. Patients were divided into three groups (n=20) according to the method of working length determination.Access was prepared followed by the placement of file which was cemented to the reference point and the tooth was extracted. After extraction, apical Sections were prepared and observed under stereomicroscope at 4.5X magnification and photographed, which were then analyzed with Image J Analysis Software. Data was statistically analyzed using SPSS version 17 software. One–way analysis of variance with student–Newman–keuls method was carried out to compare the means. The lowest mean of difference was recorded in the EAL group (0.227 ± 0.309). There was statistically significant difference between Radiographic and EAL group