Renal ischemia-reperfusion (I/R) is an important etiopathological mechanism of acute renal failure (ARF). Despite improvements in the treatment of ARF, it is associated with significant morbidity and mortality. I/R injury also occurs during renal transplantation and leads to reduced allograft survival. Sex differences have been found in I/R injury in many different organs including the kidney. Women have half the mortality of men in ARF. In animal models also, females are protected against renal I/R injury. The mechanisms by which sex affects the outcome to renal I/R injury are being actively investigated. This review will examine the evidence for gender differences in renal I/R injury and discuss the probable mechanisms by which sex affects the renal response to I/R injury.