With health care costs rising, increased attention has been paid to the human resource practices of hospitals. This chapter examines the effects that staffing levels and wages of registered nurses have on hospitals' average lengths of stay. Based on data from 352 California hospitals, we show that both increased staffing levels and wage rates relate to decreased average lengths of stay. Furthermore, based on our most complete and accurate models, it appears that wage may be more effective for improving the average lengths of stay than would increasing the quantity of RNs. The results of this chapter have a number of implications for human resource practices of RNs and for future research on health care management practices.