The smoking characteristics of shipyard workers participating in an Asbestos Medical Surveillance Program (N=3,991) were assessed. Sources of data were: (I) a self-assessment questionnaire on the smoking history and respiratory symptomatology of the 871 current smokers who participated in the smoking study, and (2) chest roentgenograms and pulmonary function test results and medical records for the entire population. The study population included 1,711 current smokers, 988 former smokers and 1,292 never smokers. The annual “quit rate” for former smokers had increased from less than 1% in 1961 to 4.2% in 1978. Of the 871 current smokers who participated in the smoking study, 19% had resumed smoking after having given up cigarettes for one year or longer. Men in the smoking study were reasonably well informed about the health consequences of smoking. While they perceived themselves to be susceptible to disease, and the disease to be serious, the benefits they saw in quitting were related more to economics and aesthetics than to health. When the results were age adjusted, no differences in rate of pulonary function abnormalities and chest film abnormalities were found between current smokers who voluntarily participated in the smoking study and those who did not. All pulmonary function testing abnormality and chest film abnormality rates were significantly lower for former smokers and never smokers.