Background: Both basic and clinical research has demonstrated that antiepileptic drugs can be effective in alleviating neuropathic pain. It was hypothesized that oxcarbazepine might be effective in reducing the symptoms of painful diabetic neuropathy. Aims: To investigate the long-term efficacy and safety of oxcarbazepine in symptoms of painful diabetic neuropathy. Materials and Methods: This study included thirty-eight painful diabetic neuropathy patients, which were screened with clinical assessment and electrophysiological studies. The efficacy and safety of oxcarbazepine were evaluated according to the changes in pain intensity and social interference subitems scores of Short-form Brief Pain Inventory besides electrophysiological studies at the end of six months of the treatment. Statistical Analysis: The Students t, Mann-Whitney U and Rank Sum test and Chi-square tests were applied to examine variables differences. The level of statistical significance was chosen to be P