The electrophysiologic findings in an infant with congenital facial diplegia (Möbius syndrome) are presented. As to serial electrically elicited blink reflexes, the R1 amplitude was significantly reduced and the R2 latency was significantly prolonged. The M response of the orbicularis oculi muscle showed slightly reduced amplitude. Auditory brainstem responses exhibited a prolonged time between waves I and V and reduced amplitude of wave V on the right side. Somatosensory evoked potentials and visual evoked potentials were normal. These findings suggest some degree of impairment of the peripheral facial nerve, and brainstem dysfunction including the pons and lateral medulla.