Physicians may need to defend their impairment evaluation opinions during cross-examination, and, in contrast to direct examination during which leading questions cannot be asked, during cross-examination the laws of evidence allow the questioning attorney to pose leading questions that are designed to elicit more information than a “yes” or “no” answer. A witness being cross-examined with leading questions typically may respond “yes,” “no,” or “I don't know,” but physicians should not volunteer information during examination because this may disclose inappropriate information. Similarly, physicians should avoid vague terms such as “I guess,” “I believe,” or “It's possible.” If the witness does not know the answer, the proper response is “I don't know,” or “I don't remember.” The expert's professional qualifications, expert opinion, and reasoning in forming that opinion are all subject to challenge, and the expert must be qualified to perform permanent impairment evaluations and prepare a report with supportable conclusions. The article includes examples of cross-examinations based on principles from the AMA Guides to the Evaluation of Permanent Impairment (AMA Guides), Chapters 1 and 2. For example, evaluators may be criticized for erroneously using the terms guidelines instead of guides and disability instead of impairment; physicians who use impairment and disability interchangeably should expect close cross-examination. Evaluating physicians also may be challenged regarding their status as “independent and unbiased” examiners based on having seen the patient only once or, as a treating physician, on numerous occasions.