During the past 12 years, 6 studies reported restoration of sensation and relief of pain in the foot by decompression of the tibial nerve and its distal branches in diabetic neuropathy. Although a positive Tinel sign related to favorable outcomes in some of the reports, this relationship was not evaluated specifically. In this study, the presence of the Tinel sign, positive or negative, over the tibial nerve was recorded in 46 patients with diabetic neuropathy and in 40 patients with idiopathic neuropathy. Outcomes were dichotomized into either a good/excellent or failure/poor category. Postoperative data were analyzed at 1 year. In diabetic neuropathy, the presence of a positive Tinel sign had a sensitivity of 88%, a specificity of 50%, and a positive predictive value of 88% in identifying patients who would have a good/excellent outcome. In idiopathic neuropathy, the presence of a positive Tinel sign had a sensitivity of 95%, a specificity of 56%, and a positive predictive value of 93% in identifying patients who would have a good/excellent outcome. It is concluded that a positive Tinel sign is a reliable indicator of successful outcome from decompression of the tibial nerve in patients with diabetes with symptomatic neuropathy, and in patients with symptomatic idiopathic neuropathy.