This self-directed learning module highlights peripheral neuropathies. It is part of the chapter on neuromuscular rehabilitation and electrodiagnosis in the Self-Directed Physiatric Education Program for practitioners and trainees in physical medicine and rehabilitation. This article specifically focuses on diagnostic criteria and classifications of peripheral neuropathy, including diabetic, alcoholic, carcinomatous, human immunodeficiency virus-associated, and critical illness polyneuropathies. Treatment options are reviewed. The causes for difficult to obtain nerve conduction studies are highlighted. OVERALL ARTICLE OBJECTIVE: To summarize the diagnosis, classification, and treatment of peripheral neuropathies.