This was a surveillance study to evaluate the safety of tolrestat (200 mg/day) in the treatment of diabetic neuropathy. 995 patients with sensorimotor diabetic neuropathy were enrolled for this study. Peripheral diabetic neuropathy was defined by the presence of symptoms and/or the absence of Achilles or patellar reflex. 862 patients completed 12 months of therapy. Adverse events were reported by 185 of 995 (18.6%) patients; of these, 117 (11.7%) reported events that were considered related to tolrestat treatment. Elevated transaminase levels were found in 27 (2.7%) patients. 49 patients withdrew from the study because of adverse events. Some objective parameters of nerve function, including tendon reflexes and muscle strength, significantly (p < 0.001) improved at the end of treatment; vibration perception threshold showed a trend to improvement. In conclusion, tolrestat demonstrated a good safety profile over treatment for 1 year. Improvements in some objective measures of nerve function were also found.