Background: The goal of this study was to evaluate the effects of gabapentin on postherpetic neuralgia. Gabapentin is a known anti-seizure medication, whose cellular mechanism of action is not well understood. Unlike other anticonvulsant, gabapentin has the advantage of a low toxicity and favorable side effect profile. If has been recently recommended for use in treatment of neuropathic pain. Methods: Twelve patients with a diagnosis of postherpetic neuralgia were prescribed gabapentin after failure of routine therapeutic regimens. The dose of gabapentin ranged 300~1800 mg per day, in three divided doses. If initial dose was ineffective and no side effects were noted, the dosages was increased by 300 mg a day in divided doses, to the maximum level for 2 weeks. Patients were evaluated for analgesia using visual analogue scale (VAS) pain score (0; no pain, 10; worst possible pain) and possible side effects. Results: A significant decrease in pain scores with gabapentin were noted. There were several mild side effects such as dizziness, somnolence, dry mouth, constipation and facial edema, without need of special treatment. Conclusions: Gabapentin may be a useful adjunct for treating intractable postherpetic neuralgia with a minimal side effects.