Backround.Few studies have been published of corneal endothelial cell density (ECD) in children, especially in relation to the age and corneal size of the individuals. The possible effect of corneal enlargement on the endothelium was studied, and the results were objectively reviewed in relation to literature reports on corneal diameter and age.Methods.ECD was assessed in 119 children aged 5 to 15 years after endothelial photography with a noncontact specular microscope (Topcon SP-1000 or SP-2000P), followed by manual digitization of cell overlays. The horizontal corneal diameter, as the visible iris diameter, was measured to 0.5-mm accuracy.Results.The mean ± SD value for ECD, calculated using all individual cell area values, was 3542 ± 510 cells/mm2(range, 2576 to 5316), whereas it was 3246 ± 416 cells/mm2(range, 2404 to 4817) if the mean cell area value from each image was used to calculate ECD. The mean horizontal corneal diameter was 11.48 ± 0.58 mm (± SD). The corneal diameter was not obviously age-related for this group, but there were clear trends for younger children to have higher ECD values than older children (p2, depending on the method for calculating ECD.Conclusions.ECD values were found to be significantly correlated to corneal diameter in children aged 5 to 15 years, and this factor should be considered in comparative studies.