Secondhand smoke (SHS) exposure causes death and disease in both nonsmoking adults and children, including cancer, cardiovascular and respiratory diseases. SHS exposure causes an estimated 46,000 heart disease deaths and 3,400 lung cancer deaths among U.S. nonsmoking adults annually. Adopting policies that completely eliminate smoking in all indoor areas is the only effective way to eliminate involuntary SHS exposure. In 2009, an estimated 696 million aircraft passenger boardings occurred in the United States. A 2002 survey of airport smoking policies found that 42% of 31 large-hub U.S. airports had policies requiring all indoor areas to be smoke-free. To update that finding, CDC analyzed the smoking policies of airports categorized as large-hub in 2010. This report summarizes the results of that analysis, which found that, although 22 (76%) of the 29 large-hub airports surveyed were smoke-free indoors, seven airports permitted smoking in certain indoor locations, including three of the five busiest airports. Although a majority of airports reported having specifically designated smoking areas outdoors in 2010 (79%) and/or prohibiting smoking within a minimum distance of entryways (69%), no airport completely prohibited smoking on all airport property. Smoke-free policies at the state, local, or airport authority level are needed for all airports to protect air travelers and workers at airports from SHS.