Physicians use the American Medical Association's Guides to the Evaluation of Permanent Impairment, 5th edition to evaluate millions of disability applicants each year. As major contributors to the chapter in the Guides devoted to assessing impairment associated with pain, we confronted the difficulties of incorporating pain into the Guides' overall evaluation system. Analysis of these difficulties is complicated by the paucity of research on the Guides, and by ambiguities and contradictions that pervade it. We propose that the ambiguities can be reduced if impairment is consistently defined in terms of organ or body part derangement, and disability in terms of activity limitations at the level of the whole person. We also propose a distinction between objective factors that may influence a person's ability to perform activities following injury. We suggest that when physicians examine disability applicants, they should evaluate both objective measures of organ or body part dysfunction and subjective reports of applicants -- especially ones regarding pain. We conclude that a comprehensive medical evaluation of disability applicant encompasses more than an impairment assessment.