Hallucinations, visual, auditory or in another sensory modality, often respond well to treatment in patients with schizophrenia. Some, however, do not and can be very chronic and debilitating. We present a patient with schizophrenia with intractable hallucinations despite state of the art care, including high-dose clozapine and transcranial magnetic stimulation. Based on the possible role of the 5-HT2A receptor in hallucinations, we treated her with the antihypertensive drug ketanserin, a 5-HT2A receptor antagonist.This significantly reduced her visual but not her auditory hallucinations, suggesting a possible role of the 5HT2A receptor in the pathophysiology of specifically visual hallucinations. This is the first time ketanserin has been described to successfully reduce visual hallucinations in a patient with schizophrenia.