We report on acute painful neuropathy following reduction of high serum glucose levels in six diabetic patients, aged 27-52 (5 males). Initial glucose levels ranging between 270 and 600 mg/dL decreased to 60-160 mg/dL following insulin, pharmacologic or dietary treatment. Four patients had long-standing untreated diabetes (3-5 years). All six patients experienced severe excruciating neuropathic pain 2-4 weeks after initiation of treatment. Pain was generalized in all, starting in the feet in 4 cases. Pain intensity prompted the use of combination therapy with various anti-neuropathic pain agents. Symptoms gradually improved in all patients, allowing discontinuation of symptomatic therapy within 3-8 months. We conclude that acute painful neuropathy can complicate the correction of high glucose levels in diabetic patients. Therefore, careful correction of glucose levels should be considered in patients with long-standing uncontrolled diabetes.