In recent years there has been an increasing interest in endodontic retreatment, dictated by a growing demand to preserve teeth, including those in which endodontic therapy had failed. When observed closely, endodontic retreatment is distinguished from routine endodontic treatment by several aspects, all of which are related to the decision whether, in specific cases, to perform retreatment, surgery or simply nothing. Understanding those aspects of retreatment is essential to its successful practice. No less important is the mastering of retreatment techniques. Because of the presence of coronal and radicular restorations as well as root canal obturation material in many candidate-teeth for retreatment, the planning of retreatment must take both obstacles into consideration. Awareness of each techniques advantages and disadvantages will lead to selection of the proper technique to be employed. The present article focuses on reviewing all those aspects of endodontic retreatment, highlighting those which may be the most important for the clinician's daily use in practice.