A photo slit lamp was used to obtain color, specular reflex, high magnification photographs of the corneal endothelium of subjects ranging in age from 3 to 88 years. Multiple areas of the cornea were examined to determine the endothelial cell population. No appreciable difference in cell density was found between the right and left eyes of the subjects nor between male and female subjects of similar age. Apparent defects in the endothelial cell coverage of Descemets membrane were found in subjects as young as 20 years of age and with increased frequency in older age groups. These defects were at times associated with variations in endothelial cell populations between the central and peripheral cornea. The average corneal cell population fell from nearly 1 million cells in the first years of life to about one third that number by the eight decade of life.