The objective of this chapter is to evaluate the role of radical nephrectomy versus partial nephrectomy in the management of renal tumors and their impact on postoperative renal function, the part played by warm ischemia and the volume of renal parenchyma preserved, as well as the role of various surgical maneuvers and their impact on postoperative renal function. This chapter will also review the current literature and my own experience regarding the role of warm ischemia and the volume of renal parenchyma preserved on the ultimate postoperative renal functional outcome following partial nephrectomy (PN).