Blink reflex could be a useful tool to differentiate facial synkinesis as one of complications of facial neuropathy, from volitional associated movements. We had performed applied blink reflex test for 23 patients with objective evidence of hemifacial weakness in which orbicularis oculi muscle(zygomatic branch) and mentalis muscle(mandibular branch) areelectrophysiologically evaluated in response to supraorbital stimulation of trigeminal nerve. For an unaffected side of face there is no evidence of positive blink reflex from the mentalis muscle. We concluded that a positive blink reflex from mentalis muscle is almost always suggestive of chronic facial neuropathy even in clinical silence of facial synkinesis, or an aberrant reinnervation after peripheral facial neuropathy, and does not electrophysiologically correlate with the severity of facial palsy.