The diagnostic criteria for asthma usually are straightforward and generally follow the Guidelines of the American Thoracic Society (ATS). The assessment of impairment and disability from asthma is complex because of the variable nature of the disease, and the AMA Guides to the Evaluation of Permanent Impairment (AMA Guides) gives physicians discretion to adjust the class of impairment based on the frequency of asthma attacks and the physician's judgment. A physician with expertise in lung disease may use the ATS Guidelines for impairment along with the AMA Guides to determine respiratory and whole person impairment, and a table compares the AMA Guides and the ATS Guidelines in support of assessing whole person impairment. An evaluation protocol addresses the steps in the process (all should be well documented): confirm the presence of asthma; determine its severity; estimate the permanent whole person impairment (a table lists classes of whole person impairment based on the AMA Guides and the ATS Guidelines); and assess work-related asthma. In some cases, an individual with airway hyperresponsiveness may not have an impairment but may have disability for specific jobs. The protocol and suggestions offered here may be practical in most circumstances for evaluating asthma impairment and disability.