A group of 339 male shipyard workers responded to an invitation via shipyards, unions, and news media to be studied for the presence of asbestosis and its functional effects. Of these, 288 were white or black, had begun working in shipyards at least 20 years earlier, and had satisfactory chest x-ray film findings; 257 underwent spirometric testing, and 199 had single-breath diffusing capacities for carbon monoxide (Dsb) determined. There were radiographic signs of asbestosis in 64 percent. Of these, 28 percent had parenchymal disease only, 37 percent had pleural disease only, and 35 percent had both. There was pleural calcification in 9 percent. In only 14 (8 percent) was the profusion of opacities greater than 1/1 by the International Labour Organization's criteria. Age was closely related to the duration of exposure to asbestos. Thus, 87 percent of the workers who had asbestosis were born from before 1900 to 1910, 70 percent of those born in 1911 to 1920 had asbestosis, 62 percent of those born in 1921 to 1930 had the disease, and 31 percent of those born in 1931 to 1940 had signs of asbestosis. Function in nonsmokers was not significantly different from the reference population except for alveolar volume; ex-smokers had significantly reduced forced expiratory volume in one second, flow rates, Dsb, and alveolar volume. The forced vital capacity and thoracic gas volume were normal. Shipyard workers who smoked resembled reference smokers except for significantly reduced alveolar volume. These shipyard workers had minimal to moderate asbestosis with much pleural disease and little functional impairment when compared to a smoking-specific reference population.