The aim of this study was to evaluate and compare the accuracy of working length (WL) determination when using the conventional electronic WL (EWL) technique versus using the novel Apexoconnection technique involving EWL with a connector (EWLc).Sixty extracted posterior teeth with a total of 118 root canals were selected for the study. The real WL (RWL) of each canal was verified using a dental microscope under 25.6x magnification. Root canal lengths were measured with an apex locator using the attachment device directly attached to the hand file in the root canal and then adding another hand file as a connector between the attachment device and the file in the root canal. The distance from the file's stopper to its tip was measured using a digital caliper. Statistical analysis was carried out to analyze the data between experimental groups.The results of the statistical test showed that the differences in the WL determined by either technique and the proper length as determined under the microscope were not statistically significant. The results of the statistical test comparing the groups were also not statistically significant.In this in vitro study, both the novel and conventional techniques were equally accurate for determining WL when compared with the RWL.