Peripheral neuropathies are among the most common neurological diseases. Various tissues are available for morphological investigation, depending on the purpose of diagnosis. The sural nerve is most frequently used for nerve biopsy. The nomenclature of neuropathies is described together with prerequisites and techniques for nerve biopsy. Morphologically, a distinction can be made between parenchymatous and interstitial lesions. An account is given of the most important morphological patterns, such as axonal and neuronal degeneration and regeneration, including Waller's degeneration, segmental demyelinisation and remyelinisation as well as hypertrophic alterations. Brief reference is made to conjunctival, dermal, and rectal biopsies.