Eighty-eight shipyard workers with extensive asbestos exposure were evaluated in terms of dyspnea, smoking history, x-ray film abnormalities, static pulmonary function, and exercise performance. Pulmonary function abnormalities and roentgenographic pleuropulmonary disease were more frequent in smokers. Significant dyspnea was present in 41 percent of the workers and did not correlate with smoking history, pulmonary function, or exercise performance. Despite this high frequency of dyspnea, 70 percent of all workers had normal exercise tolerance by history of exercise testing. Of the 26 workers with exercise impairment, only nine had pulmonary mechanical or gas exchange limitation. Two of these workers had asbestosis, while the other had airways obstruction without asbestosis. The prevalence of both asbestosis and asbestos-related exercise impairment in this population was 2.3 percent.