This article describes a technique for fabricating an interim obturator for maxillectomy patients using a microwave-polymerized denture base resin. The use of microwave irradiation to polymerize this type of resin reduces the time required to fabricate interim obturators and results in prostheses comparable in physical properties and superior in dimensional accuracy to prostheses made with conventional heat-polymerized acrylic denture base resin. The technique is simple and time efficient, and it does not require any special or elaborate laboratory equipment.