Smokeless tobacco causes cancers of the oral cavity, esophagus, and pancreas. CDC analyzed National Health Interview Survey (NHIS) data to estimate the proportion of U.S. working adults who used smokeless tobacco in 2005 and 2010, by industry and occupation. This report describes the results of that analysis, which showed no statistically significant change in the prevalence of smokeless tobacco use among workers from 2005 (2.7%) to 2010 (3.0%). In 2010, smokeless tobacco use was highest among adults aged 25-44 years (3.9%), males (5.6%), non-Hispanic whites (4.0%), those with no more than a high school education (3.9%), and those living in the South (3.9%). By industry, the prevalence of smokeless tobacco use ranged from 1.5% in education services to 18.8% in mining industries, and by occupation from 1.3% in office and administrative support to 10.8% in construction and extraction. These findings highlight opportunities for reducing the health and economic burdens of tobacco use among U.S. workers, especially those in certain industries (e.g., mining) and occupations (e.g., construction and extraction) where use of smokeless tobacco is especially common. CDC recommends best practices for comprehensive tobacco control programs, including effective employer interventions, such as providing employee health insurance coverage for proven cessation treatments, offering easily accessible help for those who want to quit, and establishing and enforcing tobacco-free workplace policies.