Malignant (invasive) otitis externa (MOE) is an infection involving the external auditory meatus (EAM), most often found in elderly diabetics, which carries a high morbidity and mortality. In advanced cases it may give rise to osteomyelitis and cranial neuropathies. This is a case of MOE, which invaded the posterior wall of the right temporomandibular joint (TMJ), resulting in severe trismus and pain. Subsequently, this required treatment by replacement of the glenoid fossa with a Silastic® prosthesis.