Objective:To observe the morphological changes of cold-stored rat kidneys flushed with multi-organ preservation solution containing ketamine.Methods: The kidneys of male SD rats were retrogradely perfused with 0-4℃ HC-A (50-100 ml) only or together with ketamine (10-5μmol/L), and were then isolated, cold stored for 24,48,and 72 h.The morphological changes of the kidneys in both groups were observed under light microscope and transmission electron microscope.Results: Light microscopy and transmission electron microscopy showed that there were evident morphological changes in the ketamine group after 72 h,with necrotic cells and organelles, and severe renal interstitial edema.The above changes in the HC-2 group were slighter.Conclusion: Ketamine in the organ preservation solution is harmful for the cold storage of rat kidneys.