Nurses in staff development are responsible for assuring nurses' competence in the delivery of care. Older patients are the predominant population in hospitals, yet there are no instruments that specifically assess the competency of nurses to deliver care to older patients. This article reports on the development and testing of an instrument, Geriatric Competencies for RNs in Hospitals, and makes recommendations as to how staff development educators can use the geriatric competency instrument with staff nurses.