BACKGROUND: Limited data suggest that moderate alcohol drinkers may have better lung airways function than abstainers. Because few studies have fully accounted for confounders (including smoking and coronary disease), and some might have been biased by the inclusion with nondrinkers of alcohol drinkers who quit because of illness, we performed a cross-sectional analysis in a large free-living population. METHODS: We studied the relation between alcohol and airways function in 177,721 members of a comprehensive health plan. An item on a questionnaire administered as part of a health examination asked for ‘usual number of drinks in the past year.’ Respondents were asked to lump ‘wine, beer, whiskey, and cocktails’ together. Health history queries included 47 items indicative of possible cardiorespiratory (CR) illness; participants with one or more positive response (61.0%) were classified as ‘CR yes.’ Lung function measurements were part of the health examination; we studied one-second forced expiratory volume (FEV(1)), forced vital capacity (FVC), and FEV(1)/FVC by analysis of covariance and FEV(1)/FVC <0.7 by logistic regression. Nondrinkers were the referent for alcohol categories; covariates were age, sex, ethnicity, smoking, education, body mass index, and CR composite yes/no. RESULTS: For each measure studied, persons reporting two or fewer drinks per day or three to five drinks per day had better airways function than nondrinkers (p < 0.001), but heavier drinkers had worse function. This J-shaped relation was consistent across multiple strata, including CR 'yes' or 'no.' CONCLUSION: Independent of smoking and evident lung or heart disease, light to moderate drinkers of alcohol had better FEV(1), FVC, and FEV(1)/FVC than abstainers did. Although this association does not prove causality, drinking moderate amounts of alcoholic beverages may have some benefit for lung function.