Aim- To compare and evaluate accuracy of fifth and sixth generation electronic apex locators in the presence of three different irrigating solutions in working length determination. Material and methods: 30 extracted human mandibular premolars were used. The crowns were cut horizontally and access cavity preparation was prepared. Working length were evaluated by three methods: Group I: control group (visible method, n=30), Group II: fifth generation apex locator (n=30), Group III: sixth generation apex locator (n=30). In control group, the root canal length were measured under stereomicroscope under 10X magnification upto apical foramen and distance were measured with digital caliper and 0.5 mm was deducted from this canal length. Group II and III were further divided into 3 subgroups based on irrigating solutions: Group A: saline (n=30), Group B: 5.25% NaOCl (n=30), Group C: 17% EDTA (n=30). Teeth were embedded in alginate mass along with metal lip clip to complete the current circuit. Teeth were irrigated with three different irrigating solutions according to three subgroups. Root canal length were taken on apex locator upto apical foramen. Then, working length were measured with a digital caliper and 0.5 mm were deducted from this length. For each tooth and the type of irrigant, three measurements were made and the mean of measurements were taken.