Exposure to environmental tobacco smoke (ETS) is a global public health problem which is particularly acute in groups where smoking rates are higher than in the general population. A study was undertaken to investigate knowledge, attitudes and preventive efforts with regard to exposure to ETS in a sample of economically disadvantaged women residing in Michigan, USA. Analysis-of-variance techniques were used to investigate how knowledge, attitudes and preventive efforts regarding exposure to ETS relate to demographic variables such as smoking status, ethnicity, education, employment, and income; and analysis-of-covariance techniques were applied to determine the degree to which knowledge, attitudes, age, smoking status, ethnicity, education, employment, income and home environment predict these women's preventive efforts regarding exposure to ETS. Generally, women with no high school diploma and women who were smokers were less knowledgeable about the adverse health effects of exposure to ETS, had worse attitudes concerning exposure to ETS and were less likely to take preventive steps to limit their exposure to ETS than were women who had more formal education or who were nonsmokers, respectively. The primary predictors of preventive efforts were knowledge, attitudes and smoking status. The results suggest that educational efforts focusing on increasing knowledge and improving attitudes regarding exposure to ETS, as well as providing practical strategies for limiting exposure to ETS, should be developed and delivered to at-risk populations.