A 46-yr-old man with a 3-month history of post treatment neuropathy following insulin treatment for diabetes mellitus was suffering from severe pain and dysesthesia in his bilateral feet and legs. The patient described his pain as constant burning sensation which was severest in the soles and extended circumferentially over the legs. Previous trials of tricyclic antidepressants and nonsteroidal antiinflammatory drugs were uneffective. The patient received a trial dose of intravenous lidocaine (200mg), which markedly decreased his pain. Subsequently, mexiletine was administered orally in a dose of 300 mg a day and the dose was increased up to 450 mg a day, by which a severity of pain was halved and anxiety was relieved one month later. In conclusion, intravenous lidocaine and oral mexiletine may be useful drugs for post treatment neuropathy.