The morphology of corneal innervation was studied in rabbits with alloxan-induced diabetes. The experimental rabbits were killed after 6, 8, 10, 12 weeks. Corneal innervation was studied by histochemical techniques and transmission electron microscopy. The results revealed that in diabetic rabbits, from 6 weeks, the density of nerve-nets was markedly sparser, the fibers were thinner and the activity of nerves was lower than those of the control group. Ultrastructural changes showed swelling of axons, irregular distribution of fibril and degeneration of mitochondria of varying degree. With the progress of disease the above changes were becoming more marked gradually. It may be assumed that these changes are related to hyperglycemia.