Changes in nerve fiber numbers distal to a nerve repair in the sciatic nerve of 48 rats were evaluated over a 1- to 24-month period. The results of the morphometric evaluation in the sciatic nerve distal to the nerve repair demonstrated an increase in nerve fiber counts as early as 1 month following the nerve repair. The number of nerve fibers in the distal nerve was greatest at 3 months and did not return to normal levels until 24 months. The results of this study will influence the timing of experimental studies in which nerve fiber counts are critical for evaluation, and provides a better understanding of the clinical events occurring following nerve repair.