Objective : Brachial plexus injury can produce a intractable chronic neuropathic pain. This study was undertaken to assess the long term outcome of microsurgical dorsal root entry zonotomy[MDT]. Methods : Between October 1997 and December 2002, 21 patients received MDT because of a intractable pain resulting from brachial plexus injury. Of these, 19 patients were followed for more than 2 years. Fourteen of 19 patients were male and patient ages ranged from 22 to 69 years. Mean pain duration was 36.8 months and all patients had severe pain of $9{sim}10$ visual analogue scale. To achieve complete destruction of abnormal dorsal horns, thermocoagulation of the posterolateral sulcus were performed and careful gluing was done to prevent postoperative adhesion and pain recurrence. Results : Of the 19 patients, 15 patients had excellent [>75% reduction in pain] and good [$51{sim}75%$ pain relief] results in a average postoperative period of 4.1 years. One patient had a poor [less than 25% pain relief] result. Three patients were considered to have a fair result [$26{sim}50%$ pain relief]. Postoperative complications were 2 transient ipsilateral ataxia and 1 CSF fistula that resolved without surgical revision. Conclusion : These results indicate that MDT provides excellent long-term pain relief in medically intractable chronic neuropathic pain following brachial plexus injury without significant complications.