Low-Energy laser is a newly developed therapeutic modality that is widely used in medical practice. It is indicated in wound healing, soft tissue injury, pain relief, arthritic condition, and so on. But, its mechanism of action is not known so far and its effect is controversial. Recently, some investigators reported that low-energy laser promoted regeneration of injured peripheral nerves in animal studies. However, some reported that they could not prove such results. We made crushing injury on sciatic nerves of 20 rats artificially and investigate effect of low-energy laser on their regeneration. The results showed no significant difference between laser irradiated rats and control rats. We could not prove beneficial effect of low-energy laser on the regeneration of injured peripheral nerves.