The term polyneuropathy (PNP) is used to describe a group of entities affecting the peripheral nerves, due to external trauma or internal pathology. The prevalence of PNP in the elderly is between 5 and 10%. Despite the multiplicity of causes, the most common etiological factor is diabetes. PNP is characterized by a wide variety of symptoms, due to the multiple functions of nerves. Clinical manifestations range from sensory or motor deficit to inability to maintain gait and stability. Diagnosis is difficult in the elderly, and can be a challenge to the geriatrician in patients with functional impairment. The gold standard for diagnosis is electrophysiology testing. The present article describes the main PNP in the elderly based on the physiopathology of these diseases and provides a practical proposal for clinical classification.