This article discusses the evaluation of peripheral nerve impairment and focuses on assessing peripheral polyneuropathies. Although peripheral neuropathy is a common neurological disorder, no uniform criteria exist for either evaluation or diagnosis, and 30% of cases remain idiopathic. The patient must be at maximum medical improvement (MMI) before permanent impairment is rated, but determining MMI is challenging, particularly if neuropathy is secondary to an underlying medical condition such as hypothyroid or diabetic neuropathy or toxic exposure. A table in this article directs readers to specific tables from the AMA Guides to the Evaluation of Permanent Impairment (AMA Guides) for determining maximum motor and sensory loss. Sensory dysfunction is evaluated by whether it interferes with performance of daily functions, and another table compares sensory gradings according to the AMA Guides, Fifth Edition (Tables 16-10 and 13-23) and the Fourth Edition (Table 11). When using these tables, evaluators should be aware of differences in terminology: sensation is the acceptance and activation of impulses in the afferent nerve fibers of the nervous system, and sensibility is the conscious appreciation and interpretation of the stimulus. In addition, a box discusses two-point discrimination testing and steps the examiner can take to minimize the variability of this procedure. Grading a sensory deficit requires considerable judgment and interpretation, which makes the findings less objective than findings that are independently verifiable.