The diagnosis of diabetic neuropathy is based on the diagnosis of diabetes, typical symptoms and clinical findings, as well as exclusion of other causes leading to neuropathy. Neuropathy that affects the large fibres can be verified objectively by ENMG and small fibre neuropathy is revealed by quantitative sensory threshold testing. The loss of small nerve fibres may also be demonstrated by skin biopsy. Neuropathy may be the first sign of type 2 diabetes.The loss of protective sensation as a consequence of peripheral neuropathy is the most important risk factor of diabetic foot ulcer. Small fibre neuropathy may already emerge during the phase of impaired glucose tolerance. 11–25% of the patients may have peripheral neuropathy in the pre-diabetic phase already.