Correlates of forced expiratory volume in one second (FEV1) and the prevalence of pulmonary disease and symptoms were examined in 6,346 Japanese-American men 45 to 68 yr of age. There was a significant inverse dose-response relationship between FEV1 and cigarette smoking measured as pack-years, number of cigarettes, or number of years smoked. Ex-smokers had FEV1 values that were intermediate to the higher values for nonsmokers and the lower values for current smokers. Among current smokers, inhaling and starting to smoke at a younger age were associated with lower values of FEV1, independent of pack-years. FEV1 was also correlated with a variety of other biologic and sociobehavioral variables, even after removing the effects of smoking. These variables included skinfold thickness, dynamometry, hematocrit, triglycerides, and systolic blood pressure. When compared with Caucasian populations, these Japanese-American men had low prevalence rates of airflow obstruction and pulmonary disease symptoms.