Objectives. To evaluate whether a laparoscopic hydro-jet device can provide a safe and effective partial nephrectomy. Partial nephrectomy is still one of the most challenging operations in urologic laparoscopy. The control of hemorrhage is very difficult to achieve with laparoscopic techniques. In open surgery, hydro-jet resection is used to cut the renal parenchyma selectively, avoiding damage to the vascular structures or collecting system. Methods. Laparoscopic wedge, as well as pole, resections of the kidney were performed in 5 pigs under general anesthesia. After exposure of the kidney, the renal capsule was incised using electrocautery. The hydro-jet was then used to dissect the renal parenchyma. In pole resections, the collecting system and central vessels were divided using an Endo-GIA. Hemostasis was achieved by electrocoagulation or clips. The dissection time and intraoperative complications were evaluated. Results. The operations were performed successfully in all animals without temporary ischemia. The hydro-jet generator allowed precise and effective tissue dissection without significant hemorrhage. The parenchyma[ vessels were selectively coagulated. The collecting system and central vessels remained intact and could be divided after application of the Endo-GIA. The mean dissection time was 42 +/-6 minutes for the wedge resections and 54 +/-8 minutes for the pole resections. Conclusions. These experimental results demonstrate the suitability of hydro-jet dissection for safe laparoscopic partial nephrectomy without temporary ischemia and with reduction of the operative trauma to the kidney. On the basis of our own experiences with other techniques, including electrocautery and laser technology for partial nephrectomy, we conclude that laparoscopic hydro-jet resection represents an interesting alternative to other techniques. UROLOGY 58: 1070-1073, 2001. (C) 2001, Elsevier Science Inc.