Background: Renal transplant (RT) is the optimal treatment for the majority of patient with End-stage renal failure (ESRF). Many studies had tried to express various roles allowing for a successful renal transplantation using many techniques and drugs applied on both donors and recipients .The only setting in which the mannitol is thought to be a useful renal protectant is in renal Transplantation, However, much of the work in this area was completed in the 1980s and early in 1990s. And according to some investigators most of these studies lack scientific rigors.Material and methods: The study included 30 recipient patients (age 18-60), suffering from end stage renal failure because of deferent etiology, of both sex, they were divided into two group according to intra-operative kidney protective management strategy given to their living donors either containing mannitol or not. Each consists of 15 patients:- In one group; the donors received a solution of mannitol 20%, at a dose of 0.5 mg/kg IV infusion intra operative, 30 minutes before vascular clamping.- The other group received routine intra-operative fluids.-Follow up data of early post operative graft function was collected over 14 days, and at 1, 2, and 3 months.Results:The total urine volume ‘was higher’ at the end of surgery and in the first two postoperative days in the mannitol group [P values of 0.046 at the end of surgery and 0.047 & 0.032 in the first & second post-operative days respectively].Serum creatinine for recipients of mannitol group recovered to normal range earlier than the other group [P value 0.038]; the serum creatinine was lower post-operatively in the mannitol group, but these differences remained statistically significant only for the first 7 post-operative days [p value of 0.018, 0.001, 0.027, 0.015, 0.009 at the end of surgery and on days 1, 2, 3, 7 respectively.]Also the mean creatinine clearance of mannitol group was significantly higher at each of the first post-operative 7 days , then showed no statistical differences in post operative day 14 , and at one ,two and three months.[p value was 0.047, 0.044, 0.043, 0.042 for postoperative days 1,2,3,7 respectively.]Despite that ultrasound reports that detected grad I nephropathy were more in the mannitol Group, this finding had no statistical significance [p value was 0.425].Renal Doppler reports of mannitol group showed no abnormality, while that of non mannitol group showed a case of thrombotic micro-angiopathy. This was confirmed by renal biopsy [p value = 0.007].The rejection of renal graft occurred only in two patients, one in each group, but the one occurring in the mannitol group was obviously due to surgical technical problems.Conclusion:Since most graft failures occur early after transplantation, it is particularly important to find methods to prevent these failures and thereby greatly improve long-term survival. So, we think according to our study, that mannitol allows a safe passage for this early but critical period of graft life; which in this study, was estimated to be the first 14 postoperative days. However, mannitol seems to have a little or no effect later on, regarding renal graft function.