Objective. We estimated the proportion of U.S. smokers who have low socioeconomic status (SES). Methods. We used 2012 data from a national supplement to The Attitudes and Behaviors Survey on Health (TABS), a periodic population survey of Colorado adults. We estimated smoking prevalence and total smokers by education, poverty level, occupation, health insurance status, and combinations of these factors. Results. Smoking prevalence across low-SES categories ranged from 24.3% to 42.6%. Combining low-SES categories with the highest smoking prevalence accounted for 31.1% of U.S. adults but half (50.1%) of smokers. Combining all low-SES categories regardless of smoking prevalence accounted for roughly half (53.3%) of adults but nearly three-fourths (72.2%) of smokers. Conclusions. A majority of continuing U.S. smokers have low SES. Further progress against the U.S. cigarette epidemic depends on focusing tobacco research and program initiatives on reaching and engaging these smokers in cessation strategies that work for them.