Polyneuropathies are common, with the incidence increasing with older age. The causes of polyneuropathies are diverse and numerous, and it can be challenging for clinicians to determine the etiology of a particular patient's neuropathy. In this article, we systematically detail a practical approach to polyneuropathies, beginning with the most important aspects of the workup, the history and physical. We then discuss the limited diagnostic approach required for patients who present with a distal symmetric polyneuropathy and the more comprehensive approach for patients who present with other neuropathy subtypes.