Most mouthguards made for edentulous mouths lack the stability to prevent dislodgement. In a case reported in the literature where stability was achieved the appliance was bulky, difficult to insert and remove and lacked permanence. To surmount these deficiencies one was designed in two halves which, when placed into the mouth, slotted together to give the stability of the one piece construction but at the same time allowed easy insertion and removal. This paper describes the construction of such a mouthguard and reports on one case.