We evaluated the hemostatic efficacy of a biological self-assembling peptide RADA16-I in a rat kidney injury model. Adult male rats were randomized into five groups: sham operation (no renal excision), no hemostatic agent (control), commercially available gelatin sponge (Gelfoam), 1% RADA16-I, and 2% RADA16-I. After left partial nephrectomy, the anesthetized animal was anticoagulated using 300 IU x kg(-1) heparin, and the topical hemostatic agent was applied to the injury. Blood loss and mean arterial pressure (MAP) were recorded. As was the case for Gelfoam, 2% RADA16-I produced marked hemostasis versus controls (p < 0.01). Blood loss with 1% and 2% RADA16-I was significantly less than controls. The decline in MAP during surgery was less with 2% versus 1% RADA16-I. RADA16-I also resulted in less histological tissue responses than Gelfoam. These data suggest that RADA16-I can stop hemorrhage, with only minimal tissue responses, in experimental renal injury.