We describe five patients with bilateral hemifacial spasm evaluated in a Movement Disorders Clinic to illustrate the clinical characteristics and to draw attention to the differential diagnosis of this condition. All patients had unilateral onset followed by bilateral, asymmetric, and asynchronous facial contractions. The mean age of the patients (4 women and 1 man) was 70.6 years (range, 54-81 yrs), and the mean duration of symptoms was 17 years (range, 2-30 yrs). The facial twitching started in the left eyelid in all cases and the opposite side of the face began to twitch on the average 8.4 years (range, 0.2-15 yrs) later. Imaging studies revealed tortuous vertebrobasilar arteries in three patients. Four patients were successfully treated with botulinum toxin injections. Bilateral hemifacial spasm is a rare, peripherally induced disorder that must be differentiated from tics, dystonia including blepharospasm and other cranial dystonia, and other facial dyskinesias. Botulinum toxin injection appears to be the treatment of choice.