Nowadays the laparoscopic kidney resection is a “gold standard” for treatment of tumor stages T1-2a. One of the most important factors is kidney thermal ischemia leading to ischemic and reperfusion damage. It’s of current importance to elaborate a nephron-sparing complex end create an effective algorithm for preoperative, operative and post-operative periods. The key problem is a choice of time interval for renal artery clamping during operation, which will not cause irreversible structural and functional kidney changes. The purpose of this experimental study is a detection of maximum safe time of ischemia with morphologic verification via electronic microscopy.Study results show that kidney epithelium keeps vitality in 30 minutes and 60 minutes of ischemia. In 90 minutes it has irreversible cells damage (necrosis). Therefore “the point of no return” for kidney epithelium is beyond one hour interval of thermal ischemia. In combination with effective pharmacologic protection this fact expands the opportunities of modern laparoscopic surgery. Refs17. Figs 8.