Purpose: Laparoscopic partial nephrectomy (LPN) is a relatively recently introduced method of treating renal tumors and, as such, surgical technique is evolving. In open series urinary fistula formation represents a common postoperative complication. In the laparoscopic approach investigators have advocated the placement of a ureteral catheter with retrograde dye injection to visualize caliceal entry to aid in closure. In this study we assessed the necessity of ureteral catheter placement during LPN in decreasing urinary leakage. Materials and Methods: From February 1998 until November 2002 laparoscopic partial nephrectomy was performed in 103 patients with renal tumors. The patients were assessed retrospectively and divided into 2 groups according to placement (group 1) or no placement (group 2) of an external ureteral catheter. Group 1 included 54 patients (mean age ± SD 57.4 ± 13.4 years) and group 2 included 49 patients (mean age ± SD 57.5 ± 10.9). Intraoperative and postoperative parameters including blood loss, operative time, ischemia time, mass size, complications and hospital stay were reviewed and compared between the 2 groups. Results: There were no differences between the 2 groups in mean estimated blood loss (group 1, 394.7 cc vs group 2, 291.5 cc, p = 0.07), postoperative serum creatinine (group 1, 0.95 mg/dl vs group 2, 0.89 mg/dl, p = 0.12), requirement for pain medication (group 1, 8.9 mg vs group 2, 4.9 mg morphine equivalents, p = 0.12), hospital stay (group 1, 3.1 vs group 2, 2.9, p = 0.29) and warm ischemia time (group 1, 28 minutes vs group 2, 26.5 minutes, p = 0.18). Mean total operative time was significantly longer for group 1 compared to group 2 (191.1 vs 149.4 minutes, respectively, p = 0.001). Postoperative urinary leakage requiring prolonged drainage occurred in 1 patient in group 1 and 1 in group 2. In both cases caliceal entry was identified and sutured. Conclusions: With experience caliceal entry can be identified without the need for a ureteral catheter in patients undergoing LPN for a tumor less than 4.5 cm. Urinary fistula may occur despite caliceal entry and repair. A ureteral catheter may not decrease urinary fistula in patients undergoing LPN.