Perioperative hemorrhage is still the major complication of standard transurethral prostate resection (TURP). Potassium titanyl phosphate (KTP) laser vaporization using 80 W is a novel technique that promises instant hemostatic tissue ablation. In this ex vivo investigation we compared the hemostatic properties of the 2 procedures. Ex vivo, blood perfused porcine kidneys were used to verify the hemostatic efficacy of KTP laser vaporization and TURP-like tissue resection. Bleeding could be exactly quantified in relation to tissue ablation for the 2 techniques. In addition, specimens were examined microscopically. KTP laser vaporization demonstrated highly significantly decreased bleeding as compared to conventional tissue resection for a standardized ablation volume of 16 cm tissue (2.1 vs 23.3 ml per minute, p <0.0001). Tissue ablation was more rapid in the resection group (20 vs 100 seconds, p <0.001). Histological examinations revealed larger coagulation zones for the KTP group compared to conventional tissue resection (0.9 vs 0.6 mm, p <0.01). Ex vivo, 80 W KTP laser vaporization is a virtually bloodless ablative procedure, giving rise to hemostasis that is highly superior to conventional TURP-like tissue resection. However, the novel procedure is considerably more time-consuming.