Three flush out and cold storage solutions were tested for flow rate during flush out, ability to decrease organ temperature, degree of tissue edema and degree of preservation damage of the kidney as measured by the amount of post transplantation erythrocyte trapping in the renal medulla. The solutions tested were a modification of a new perfusion solution (University of Wisconsin; mUW), a standard preservation solution (Sacks') and an extracellular histidine solution (Frödin-Wolgast; FW). The flow rate was significantly higher for FW compared to mUW and Sacks' and consequently a more rapid decrease of organ temperature was achieved. The results also show that edema formation as well as the amount of erythrocyte trapping was lower in kidneys stored in mUW, indicating that mUW is better cold storage solution than Sacks' or FW.