The purpose of this study is to compare the performance of laparoscopic partial nephrectomy (LPN) with and without clamping of the renal artery and to evaluate the impact of clamping on postoperative renal function. A total of 20 patients underwent LPN, 13 without and 7 with clamping of the renal artery. The 2 groups were compared with respect to complications, blood loss, operative time, mean tumor size, and incidence of positive margins. Renal function was evaluated by pre- and postoperative renal scintigraphy using 99m Technetium-mercaptoacetyltriglycine (99mTc-MAG3). Intraoperative blood loss was significantly higher in the group without clamping than in the group with clamping (p0.04). In the group with clamping, the median warm ischemic time was 35 min (range 25-40 min). The serum creatinine values and the renal scintigraphy showed no influence on postoperative renal function with or without clamping. In the group without clamping, 2 cases were showed positive surgical margins. The procedure performed with clamping of the renal artery is superior to the procedure performed without clamping as it provides the advantages of controlling hemorrhaging without injury to renal function and prolonging the surgical time and allowing for more accurate resection of renal tumors.