Background: Peripheral nerve injury is one of the most challenging of modern surgical problem. Recent advances in understanding the physiological and molecular pathways demonstrated the important role of growth factors in peripheral nerve regeneration. Platelet-rich plasma (PRP) is a biological product that has many growth factors. The aim of this study was to investigate the effect of PRP in the regeneration of sciatic nerve crush in the rat model. Methods: In this experimental study that established in the animal lab of the Hazrat Fatemeh Hospital in Tehran from September to October 2013, Twenty-four healthy male Sprague-Dawley rats (200-250 g) were randomly divided into two groups. In all rats the sciatic nerve was cut and then carefully repaired by the tension free method under a light microscope. In group 1, after the repair, 0.05 µL of PRP was injected below the epineurium to the proximal and distal parts of the repaired area. In group 2 the same amount of normal saline was injected to the proximal and distal of the repaired area. After six weeks footprint analysis, neurophysiologic and histopathology evaluations were performed. Results: Significant differences existed between the two groups footprint analysis (P= 0.001). Also the nerve conduction latency test was significantly shorter in PRP group. (1.0233 ms in PRP group and 1.7375 ms in control) (P< 0.001). The average amplitude in the first group and the second group was 7.6250 mv (control) 6.3667 mv that does not show a statistically significant difference (P= 0.093). Significant differences between the two groups in the number of axons of the proximal portion of the study was not seen (P= 0.29). The parameters included number of axons of the proximal and the distal part of axons, the diameter of the distal and proximal axons in the two groups were compared. In the two groups there was statistically significant difference between the above parameters. (P= 0.298). Conclusion: It seems that PRP may have an important role in peripheral nerve regeneration and functional recovery after nerve laceration and repair. Further clinical evaluation recommended.