The pain of angina pectoris and myocardial infarction is sometimes referred to the head and neck region. The mechanism for this effect remains obscure. A case is presented here that reports that electrical stimulation of a cardiac branch of the left vagus nerve in humans can cause referred craniofacial pain. This leads to the hypothesis that the vagus nerve plays a role in mediating this pain. A review of the clinical and physiologic literature supports this hypothesis.