The scarcity of kidneys for transplantation impels an expansion of the donor source to include the use of organs from Maastricht II and Maastricht I non heart-beating donors. The aim of this study was to establish the best method to preserve kidneys from non heart-beating donors (NHBD): cold static storage (CSS) or perfusion. ATP production during kidney preservation has been retained as a measure of their energetic levels and, consequently, their viability. The presence of warm ischemia with both types of preservation was studied.