Pain is the most common presenting complaint at an impairment evaluation. In the AMA Guides to the Evaluation of Permanent Impairment (AMA Guides), the term chronic pain is synonymous with chronic pain syndrome. The AMA Guides differentiates between pain of longstanding duration, termed persistent pain, and chronic pain syndrome, which is characterized as “the devastating and recalcitrant type [of pain] with major psychosocial consequences.” Persistent pain may exist in the absence of chronic pain syndrome, but chronic pain syndrome always presumes the presence of persistent pain, according to the AMA Guides. The assessment of chronic pain syndrome involves a multidimensional approach, and a physical examination alone may be misleading. Chronic pain syndrome is a biopsychosocial phenomenon of maladaptive behavior, and the AMA Guides describes diagnostic criteria for chronic pain syndrome. In addition, this article includes a checklist of characteristics shared by chronic pain patients, along with a list of essential questions that evaluators can ask in assessing pain and a list of pain, behavioral, and psychological inventories commonly used in independent medical evaluations. Physicians should choose a battery that is consistent with the needs of the assessment, and the final report should explain the findings and significance of the inventories used.