Abstract: Previous studies have demonstrated that ligation of the sciatic nerve increases beta-endorphin binding sites both distal and proximal to the site of nerve injury. Other studies have demonstrated an increase in mu-opioid receptor (MOR) expression levels proximal to the site of nerve constriction in a model of neuropathic pain (Ann Neurol. 53:366, 2003). In the current study, we investigate axonal transport of MOR and delta-opioid receptors (DOR) to the site of nerve injury in a model of neuropathic pain induced by chronic constriction of the sciatic nerve. Immunocytochemical and immunoblotting techniques were utilized to quantify and localize opioid receptors in the dorsal root ganglia (DRG) and sciatic nerve. MOR protein levels were significantly elevated in DRG and sciatic nerve ipsilateral to the peripheral nerve injury compared to the contralateral side. A significant increase in DOR protein was observed in the sciatic nerve ipsilateral to the injury. Overall the results suggest increased MOR and DOR protein synthesis and enhanced axonal transport ipsilateral to the site of injury, in a model of neuropathic pain. Taken together, these findings indicate that peripherally-acting opioid analgesics may have therapeutic potential in the treatment of neuropathic pain.