Cold storage of kidneys before transplantation is problematic because of limited survival time of the allografts. In this study, Zinc-N-acetylcysteine (ZnNAC) was shown to be a potent endonuclease inhibitor and antioxidant, and it was tested as a potential additive to a cold storage solution for kidney preservation. Exposure of normal rat kidney NRK-52E cells to ZnNAC resulted in zinc delivery to the cells determined by TFL-Zn fluorophore and partial protection of the cells against injury by cold storage in the University of Wisconsin solution (UWS) as measured by propidium iodide assay. Ex vivo, rat kidneys demonstrated time- and temperature-dependent DNA fragmentation assessed by TUNEL assay, indicating irreversible cell death. The DNA fragmentation was faster in medulla than in cortex, and tubules were affected more than glomeruli. Perfusion of rat kidneys with cold ZnNAC solution in UWS significantly inhibited cell death both in the cortex and medulla at concentrations 0.3-30 mM as compared to UWS alone, with the maximum effect at 1-10 mM ZnNAC. Cold storage of the kidney significantly increased quantities of cleaved caspase-3 and endonuclease G in the tissue which was abolished by 10 mM ZnNAC indicating its ability to suppress both caspase-dependent and -independent cell death. Therefore, supplementation of UWS with ZnNAC can decrease DNA fragmentation and protect kidney allograft from cell death due to cold storage.