We aimed to evaluate the accuracy of 2 apex locator integrated endodontic motors during retreatment of root-end resected teeth by using 40 extracted incisor teeth. The apical 3 mm of the roots were resected, and the root lengths were recorded as resected length of the roots. Forty roots were randomly divided into 2 groups of 20 to evaluate the 2 handpieces, Tri Auto ZX and TCM Endo V. The working lengths measured during the auto reverse function and during the electronic apex locator function with Tri Auto ZX and TCM Endo V were recorded and compared with resected length of the roots. The repeated measures analysis of variance was used for statistical analyses. Electronic apex locator functions of both devices might be used for apical accuracy, but the auto reverse functions might not be useful to 0.0-mm accuracy in retreatment procedures of root-end resected teeth.