The aim of this study was to test the hypothesis that the use of an operating microscope improve the results of peripheral nerve repair. Tibial nerve grafting was carried out on 48 Fischer rates divided into 2 groups: in one, a loupe was used, and in the other a surgical microscope. At 5 months after grafting, recovery was evaluated by functional, electromyographic, and morphometric tests. The mean motor nerve conduction velocity was 26.77 ± 9.37 m/sec in the group where the loupe was used compared with 44.19 ± 11.36 m/s when the microscope groups was used. The soleus muscle weight and the diameter of myelinated fibres also confirmed better regeneration in the microscope group. These results clearly indicate that it is essential to use the microscope for peripheral nerve repair.