Precise measurement of cognitive, psychiatric, and behavioral symptoms is essential to understanding clinical, pathophysiologic, and treatment aspects of Alzheimer's disease and other dementing illnesses. The Neurobehavioral Rating Scale (NRS) is a 28-item observer-rated instrument that measures a broad range of cognitive and noncognitive symptoms. The interrater reliability of the NRS was examined in 15 patients with dementia. The correlation coefficient for the NRS total scores was .93. Coefficients for NRS factor scores and individual item scores were also satisfactory. Correlations for measures of subjectively experienced symptoms were acceptable, but less robust than measures of cognition and observable behavior. These results support the reliability of the NRS for multidimensional assessment of patients with dementia.