Peripheral neuropathy is a common symptom throughout the population, with numerous possible etiologies. The diagnosis of peripheral neuropathies (and their causes) is mainly based on clinical, electrophysiological, biological, and imaging features. Areas covered: This paper reviews the main causes of neuropathy and discusses the usefulness of nerve biopsy (NB) in such cases. Expert commentary: In most cases, NB is not mandatory in the diagnostic work-up of a peripheral neuropathy. However, NB is clearly an indication in cases of vasculitis. It is also valuable in peripheral neuropathies with severe and rapid worsening (without clear cause) in order to uncover a pathological hallmark (amyloid deposits). Although NB is considered an invasive method, it may be useful in the management of peripheral neuropathy, especially to guide treatment in certain cases. In summary, although NB is not a systematic procedure, it is a useful tool that should be discussed on a case-by-case basis within the clinical context.