Effective tobacco control efforts have resulted in substantial declines in tobacco use and tobacco-related cancer deaths in the United States. Nearly 40% of reductions in male lung cancer deaths between 1991 and 2003 can be attributed to smoking declines in the last half century. Nevertheless, tobacco use still remains the single, largest preventable cause of disease and premature death in the United States. Each year, smoking and exposure to secondhand smoke result in nearly half a million premature deaths of which nearly one-third are due to cancer. In a previous report, we described youth and adult smoking prevalence and patterns and discussed policy measures that had proven effective in comprehensive tobacco control. In this report, we update trends in youth and adult smoking prevalence. We find that while adult smoking prevalence has declined overall, socioeconomic gradients in smoking still persist within race and ethnic subgroups. In addition, we describe the diffusion of tobacco-control strategies at the national, state, and community level. Although recent developments, such as the Food and Drug Administration's (FDA) regulation of tobacco products, hold promise for tobacco control, there continues to be a need for broader dissemination of sustainably funded comprehensive national and state tobacco-control programs. CA Cancer J Clin 2009;59:352–365. © 2009 American Cancer Society, Inc.