In a one-year period, 41 patients suffering from dementia presented to a large psychiatric hospital; four were found to have reversible etiologies. In addition, 16 elderly patients with admission diagnoses of depression were found to be suffering from dementia also; 13 cases were reversible. The percentage of patients with reversible dementia is shown to be similar to percentages encountered in neurological and medical services. The results support the value of thorough psychiatric and neurologic evaluation to determine if the dementias of patients presenting to a psychiatric service are reversible. However, patients also diagnosed as depressed should first be treated for depression; more expensive and invasive diagnostic procedures should be conducted only for depressed patients who do not recover from their dementia in the course of treatment.