We report on a patient with HD, whose involuntary movements and psychiatric symptoms were clinically improved with perospirone, a second-generation antipsychotic agent with antagonistic effects on serotonin 5-HT(2A) and dopamine D(2) (D(2)) receptors, as well as a unique agonistic effect on serotonin 5-HT(1A) (5-HT(1A)) receptors.