We report a patient with dementia in Alzheimer's disease (ICD-10) in whom respiratory dyskinesia was induced by withdrawal of neuroleptics. A 68-year-old man, with dementia in Alzheimer's disease, was hospitalized for paranoid delusions and auditory hallucination. He was treated with haloperidol 6mg and sulpiride 400mg per day. Within 2 weeks, he was free from these symptoms. With discontinuance of haloperidol, the patient developed an irregular respiratory rate and gasping with abnormal involuntary movements of the mouth, tongue, and upper trunk. Auscultation revealed no abnormalities. Electrocardiogram were normal. The peak flow on respiratory function test was remarkably decreased during this episode. Magnetic resonance imaging scan of the head revealed generalized atrophy of the brain. Breathing impairment disappeared during sleep, but worsened with anxiety or pain. Respiratory dyskinesia was improved with short term administration of biperiden and disappeared with haloperidol.Respiratory dyskinesia involves abnormal involuntary movements of the respiratory musculature, resulting in respiratory difficulties. This is associated with the administration of neuroleptics and has been considered a variant of tardive dyskinesia. It has been reported that nearly one of six of the patients with tardive dyskinesia shows clinical evidence of respiratory dyskinesia. Abnormal respiration or acute respiratory alkalosis in patients taking antipsychotic agents should raise the clinician's suspicion of respiratory dyskinesia. Because tardive dyskinesia occurs more frequently in the elderly, clinicians must be cautious in treating elderly with neuroleptics.