Tobacco use remains the single most important preventable cause of premature death and disability in the United States and is a critical health issue for our nation’s youths. Cigarette smoking is the most common form of tobacco use among adolescents (Centers for Disease Control and Prevention, 2001), with over 90% of adult smokers initiating smoking at or before age 19 years (Mowery, Brick, & Farrelly, 2000). Consequently, reduction of tobacco use during adolescence is especially critical before lifelong smoking habits are established. Current national health objectives for children and adolescents focus on reducing health risks related to tobacco use and exposure to secondhand smoke (U.S. Department of Health and Human Services, 2000). Specific objectives include reducing the initiation of tobacco use among children and adolescents, reducing their average age of first use of tobacco products, increasing cessation attempts by current smokers, and reducing the proportion of children who are regularly exposed to tobacco smoke in the home. These health objectives are especially important for children and adolescents with cancer, who may be at even greater risk than their healthy peers for tobacco-related health problems because of their compromised health status (Hollen & Hobbie, 1996). Exposure to environmental tobacco smoke (ETS) has similar serious consequences for the child with cancer (Alligne & Stoddard, 1997; Cook & Strachan, 1999). Interventions that attempt to prevent, reduce, or terminate tobacco use and ETS exposure could therefore contribute to a decrease in the morbidity and mortality of patients treated for cancer. This chapter reviews the prevalence of tobacco use, the magnified health effects associated with tobacco use, and some of the correlates associated with tobacco use among young patients treated for cancer. We also describe tobacco interventions that have been conducted with this population and discuss how health care providers involved in the treatment or long-term care of childhood cancer patients can assist their high-risk patients in making healthy lifestyle choices, including the decision to abstain from, reduce, or quit smoking and to avoid environmental tobacco exposures. Tobacco use is a significant behavioral health problem that poses serious health risks for young patients treated for cancer.