Few studies have examined the relation between passive smoking and dietary intake in a large population. This report examines the nutrition and behavioral characteristics of 3,896 nonsmoking women from the first National Health and Nutrition Examination Survey (NHANES I) population in relation to exposure to environmental tobacco smoke. The data indicate that nonsmoking women who were exposed to husbands who smoked were more likely to be older, have lower education, live in the city, and have other health behaviors that could increase their risk of lung cancer compared with nonsmoking women with husbands who did not smoke. The nonexposed women were more likely to take vitamin supplements, to not drink alcohol, and to consume higher levels of dietary vitamin A, vitamin C, and calcium. The exposed and nonexposed women showed no difference in the levels of fatty acid intake nor in the levels of several other foods from the food frequency list after correction for age. Many of the differences that the authors observed between the women who were exposed and nonexposed to passive smoking could affect the risk of cancer. Therefore, they recommend that future studies of nonsmokers examine the influence of both passive smoking and diet on the risk of disease rather than examine the influence of a single factor.