Exposure to secondhand smoke (SHS) from cigarettes causes an estimated 41,000 deaths among nonsmoking U.S. adults each year and an estimated $5.6 billion annually in lost productivity caused by premature death. In a 2006 report, the Surgeon General concluded that there is no risk-free level of exposure to SHS. Although an increasing proportion of the population is covered by state or local comprehensive smokefree laws that prohibit tobacco smoking in all indoor public places and worksites, including restaurants and bars, millions of nonsmokers continue to be exposed to SHS in areas not covered by smokefree laws or policies, including homes. The home is the primary source of SHS exposure for children and a major source of exposure for nonsmoking adults. To assess progress toward increasing the proportion of households with smokefree home rules, CDC analyzed the most recent data from the Tobacco Use Supplement to the Current Population Survey. Households were considered to have a smokefree home rule if all adult respondents aged ≥18 years in the household reported that no one was allowed to smoke anywhere inside the home at any time. The analysis found that the national prevalence of smokefree home rules increased from 43.0% during 1992-1993 to 83.0% during 2010-2011. Over the same period, the national prevalence of smokefree home rules increased from 56.7% to 91.4% among households with no adult cigarette smokers and from 9.6% to 46.1% among households with at least one adult smoker. Enhanced implementation of evidence-based interventions (e.g., comprehensive smokefree laws, voluntary smokefree home rules, smokefree multiunit housing policies, and initiatives to educate the public about the health effects of SHS) is warranted to further reduce SHS exposure in the United States.