Myoclonus is manifested in a variety of situations including metabolic derangements, brain lesions, epilepsy, and drugs toxicity. We reported a rare case of amitriptyline-induced myoclonus. A 64-year-old man with a tension-type headache was administered amitriptyline at 15 mg/day. Eight days after initiation of amitriptyline, multifocal myoclonus developed, involving the face and upper extremities. Two hours after the administration of clonazepam at 1 mg, myoclonus resolved completely.