About 90% of nonsmoking people in the US are exposed to ETS. More than 50 chemicals identified in ETS have been found to cause cancer and exposure has been linked to heart disease in adults and SIDS, ear infections and numerous respiratory problems, including asthma in children. In 2007, the Environmental Protection Agency and the Office of Head Start-a national program that provides economically disadvantaged children services to enhance their social and cognitive development-announced a new initiative to promote smoke-free homes for children in Head Start programs. Because Head Start reaches high-risk, low-income preschool children, it offers a timely intervention for reducing children's exposure to ETS. Head Start also attempts to engage parents, which is an important component of reducing household ETS exposure among children. This study will determine the effectiveness of a home-delivered, motivational interviewing-based program in reducing ETS exposure and improving lung health among children who are enrolled in the Baltimore City Head Start program and whose households include a smoker.