Transection of a peripheral nerve in neonatal rats induces death of axotomized neurons, but it is not fully understood whether death is due to necrosis or apoptosis. In present investigation, neuronal death of L5 dorsal root ganglion (DRG) neurons was evaluated. Unilateral sciatic nerve transection was done on neonatal rats evaluated. Unilateral sciatic nerve transection was done on neonatal rats with ages of 1, 3, 5, 7 and 10 days old. After 5 days, right (experimental) and left (control) DRGs in all groups were removed, fixed in Bouins or Glutaraldehide solutions. Healthy nucleoli were counted in paraffin serial sections and correction factors for the split and multiple nucleoli were obtained according to Schmalbruch (1987). M~rphological appearance of neuronal death was also investigated using light and transmision electron microscopes. Results showed that number of neurons of right DRG, comparing with control, significantly reduced in all groups, and percentage of reduction for the age of 1, 3, 5, 7 and 10 was 32.4%, 27.2%, 23.8%, 22.8% and 21.8% respectively. Neuronal cell death also indicated typical morphological of changes of apoptosis including condensed typical morphological of changes of apoptosis including condensed basophil nuclei, the formation of nuclear cap, cell shrinkage and apoptotic bodies. In conclusion, after transection of a peripheral nerve, neurons died due to the of apoptosis and their reduction is age dependent.