We compared endothelial preservation of paired corneas by scanning electron microscopy after storage in McCarey-Kaufman medium for two or three days to 2.5% chondroitin sulfate (K-Sol) for seven or ten days. One cornea from each of ten pairs of eyes was placed in McCarey-Kaufman medium and the opposite cornea was placed in K-Sol medium. We judged cellular preservation in a masked manner from the electron micrographs according to a morphologic grading system. We found no difference in endothelial structure between the two groups of corneas.