Chronic constriction injury (CCI) is a common clinical entity and characterized by allodynia or spontaneous neuropathic pain. Treatment of neuropathic pain is difficult, because a lack of knowledge about the underlying mechanisms and limited effectiveness of the existing drugs. Surgical decompression enables a more radical treatment by releasing the compressed nerve. Beside the pain behaviour morphological changes occur in CCI. Ultrastructural morphological changes at the injury site of the sciatic nerve and in the dorsal root ganglia (DRG) are believed to play role in the pathogenesis of CCI and in the development of neuropathic pain behaviour in individuals. However, the effects of surgical decompression on the ultrastructure of constricted nerve site as well as in the dorsal root ganglia have not been studied in details. We investigated the effect of nerve decompression on ultrastructure of rat sciatic nerve and DRG by light and transmission electron microscopic methods. For this aim, CCI was established on the rat sciatic nerve with four loose ligatures. Surgical decompression was held at 1st, 3rd and 5th the weeks after CCI by removing the ligatures. Our results suggest that the efficacy of decompression was superior when applied one week after compression. The results of the study verify the need for early surgical decompression to prevent irreversible damage of the peripheral nerve and DRG.