In September 2004 the American Thoracic Society released a revised set of guidelines for the clinical diagnosis of nonmalignant asbestos-related disease (Am J Resp Crit Care Med. 2004;170:691-715). The conditions of concern are asbestosis, pleural disorders, and chronic airways obstruction. The criteria are evidence of structural lesion consistent with asbestos-related disease, evidence of causation by asbestos, and exclusion of alternative diagnoses. Findings that satisfy each are described. These guidelines are an extension of the 1986 ATS criteria and expand on them by establishing three explicit criteria, accommodating newer diagnostic modalities, recommending evaluation of impairment appropriate to the diagnosis, and outlining initial management measures following diagnosis. A history of significant asbestos exposure obligates the responsible physician to provide a management plan for the patient that takes into consideration current disease, impairment, and future risk. Persons identified as having asbestos-related disease or having significant exposure histories may benefit from management directed at preserving lung function, preventing complications, reducing the risk of lung cancer, and screening for potentially treatable asbestos-related disease including malignancies. Various issues arising since the publication of the guidelines are addressed, including evidence for pleural plaques being a marker of risk for lung disease apart from history of asbestos exposure; evidence against smoking being associated with a greater frequency of pleural plaques; an association between asbestos exposure and colon cancer; the diagnostic sensitivity of the chest film in smokers; and affirming the adequacy of findings on plain chest films as sufficient for the diagnosis of nonmalignant asbestos-related disease but not always sufficient to rule it out.