Fifteen patients with dementia and agitated behavior were treated in a 9-week structured trial of risperidone. Agitation remitted in all patients, and aggressive behaviors improved early in the course of treatment. The modal optimal risperidone dose was 0.5 mg/day. Extrapyramidal symptoms developed at some point during the trial in eight patients, and cognitive skills declined in three patients. These results indicate that risperidone is effective for treatment of agitation in elderly patients with dementia, although adverse extrapyramidal or cognitive effects may occur, even with low doses.