Good practice guidelines recommend the use of rubber dam for all nonsurgical endodontic procedures; there are also safety and medico-legal implications. However, many unfounded reasons have been cited for not using rubber dam. By explaining why it is essential when performing endodontic treatment, and describing the various techniques of placement, the hope is that it will encourage the routine use of rubber dam in everyday clinical practice. Keywords: asepsis, medico-legal, rubber dam