In January 1983, the department of rehabilitation nursing at the Arkansas Rehabilitation Institute (ARI), Little Rock, AR began the process of developing a patient classification system (PCS). Previously, patients were subjectively classified in one of three categories: self-care, partial care, or heavy care. This system did not adequately quantify nursing care hours nor justify the staffing pattern. Consequently, a new patient classification system was sought. This paper will provide information on the process used to develop and implement a patient classification system (PCS) using the GRASP system.