Because persons with cognitive impairment often cannot self-report pain, it is imperative to develop instruments that use observable indicators. The purpose of this study was to develop and test the psychometric properties of the Discomfort Behavior Scale (DBS), which is comprised of 17 items from the Minimum Data Set (MDS). MDS data from 29,120 cognitively impaired nursing home residents were used for psychometric testing. Factor analyses of the DBS indicated that it reflects a single discomfort dimension. The items are tau equivalent, allowing unity weighting and simple summation to create scale scores, and the internal consistency was good. The DBS has potential to be useful in studies of efforts to improve pain management in cognitively impaired residents of nursing homes.