Objectives. To compare the outcomes of laparoscopic partial nephrectomy (LPN) performed with and without vascular clamping and to evaluate the impact of clamping on postoperative renal function. Methods. A total of 45 patients underwent LPN, 29 with and 16 without vascular occlusion. The two groups were compared regarding complication rates, blood loss, conversion rates, operative time, mean tumor size, and incidence of positive margins. Renal function was evaluated by postoperative dimethyl mercaptosuccinic acid scans. Results. The mean blood loss was lower when vascular clamping was applied (320 versus 510 mL, P <0.05) than when it was not. The conversion rates were similar (10.3% versus 12.5%), and the mean operative time was shorter in the nonclamped group (115 versus 126 minutes). Urinary leakage occurred in 2 patients, 1 from each group. The mean tumor diameter was 3.2 cm in the clamped and 1.9 cm in the nonclamped group (P <0.05). In 2 patients (12.5%) in the nonclamped and 1 patient (3.4%) in the clamped group, the surgical margins were focally positive for tumor. The mean warm ischemia time was 28 minutes, and dimercaptosuccinic acid scans performed in 18 patients showed normal ipsilateral renal function (mean relative function 48%). Conclusions. LPN without vascular clamping is feasible in selected cases. However, clamping of the artery seems to be associated with reduced blood loss and a lower incidence of positive margins. Moreover, according to the postoperative dimercaptosuccinic acid scan findings, limited warm ischemia does not seem to result in permanent renal damage. We suggest that clamping of the renal artery should be considered during LPN, even for very small, superficial tumors.