Purpose: The purpose of this study is to determine the effect of platelet-rich plasma (PRP) on rat sciatic nerve regeneration in a 10 mm silicone chamber. Methods: A total of 6 inbred Lewis rats were used in this study. Bilateral sciatic neurectomy was performed on each rat. On one side, silicone chambers containing PRP solutions were implanted; on the contralateral side, the chambers without PRP were implanted as a control. In 12 weeks post-implantation, chambers were retrieved and both gastrocnemius muscles were excised. Nerves biopsy samples were examined under a light microscope after Masson trichrome staining. Results: Cross sections of the midpoints of PRP treated nerves were significantly larger and appeared more mature than those of controls. Conclusion: Based on morphological evidence, PRP has a positive effect on neural regeneration, and it may therefore be useful for treating peripheral nerve injuries.