Huntington’s disease (HD) is a progressive, inherited, debilitating disease with onset between 30 and 50 years of age. The disease has a slow progress and affects patient’s ability to think, talk and move by degeneration of the cells in the basal ganglia. Huntington’s disease is characterized by chorea, but some other movement disorders including dystonia and bradykinesia also occur. Patient may also present with psychiatric symptoms such as depression, apathy, anxiety, and psychosis. Prevalence of psychiatric symptoms ranges from 35% - 75%. Suicide rates among patients with HD are 4–6 times higher than the general population. Psychosis occurs in HD with a frequency of 6% to 25%. The most common type of psychosis in HD patients is the paranoid form. Patients with an early-onset HD have a greater risk of developing psychosis. Most studies have shown beneficial effects of typical and atypical antipsychotics in HD accompanied with psychosis. The important part of the treatment is that both neurologic and psychiatric features of the patient’s presentation had to be considered, when choosing the medication. In the present article, we concentrated on pharmacotherapy for psychotic symptoms in the management of Huntington’s disease. A 49-year-old man with Huntington’s disease of 7 years’ duration was presented with agitation, aggression, paranoid ideation and persecutory delusions that had begun 8 months ago. He had been treated with 15 mg/day olanzapine in an ambulatory care clinic. Due to the unsatisfactory control of the psychiatric symptoms, the dose of olanzapine had been reduced and stopped gradually. Risperidone had been added on the treatment and gradually raised to 2 mg daily. This change had not been effective in the psychotic symptoms; however, there had been an improvement in aggressive behaviors. He presented with a psychosis accompanied by aggressive behavior leading to admission to the locked ward of our hospital. Clozapine was ordered to the patient and the dose was gradually titrated from 25 mg/day to 300 mg/day. Based on the persistent psychosis with paranoid ideation, amisulpride was added to the treatment. His delusions improved slightly, and further add-on treatment with amisulpride (800mg daily) brought a further beneficial effect on psychotic symptoms. The patient’s aggressive behaviors reduced and eventually got better; then he was discharged from the hospital. Seen in our ambulatory care clinic that the patient had some psychotic symptoms (jealousy delusions) persisting. The results of recent researches on the role of clozapine in the treatment of Huntington’s disease (HD) and other movement disorders is not clear enough. The effect of clozapine on chorea and functional disability is studied more commonly. The atypical neuroleptic clozapine has an extremely low incidence of extrapyramidal side effects and is thought to be favorable in the treatment of chorea. Most clinical trials have shown also a resolution or improvement with clozapine in psychotic symptoms accompanying Huntington’s disease (HD). This case shows that atypical antipsychotics such as clozapine may be used to control psychotic symptoms in Huntington’s disease but not always are efficacious enough.