Quitting smoking is beneficial to health at any age, and cigarette smokers who quit before age 35 years have mortality rates similar to those who never smoked. From 1965 to 2010, the prevalence of cigarette smoking among adults in the United States decreased from 42.4% to 19.3%, in part because of an increase in the number who quit smoking. Since 2002, the number of former U.S. smokers has exceeded the number of current smokers. Mass media campaigns, increases in the prices of tobacco products, and smoke-free policies have been shown to increase smoking cessation. In addition, brief cessation advice by health-care providers; individual, group, and telephone counseling; and cessation medications are effective cessation treatments. To determine the prevalence of 1) current interest in quitting smoking, 2) successful recent smoking cessation, 3) recent use of cessation treatments, and 4) trends in quit attempts over a 10-year period, CDC analyzed data from the 2001--2010 National Health Interview Surveys (NHIS). This report summarizes the results of that analysis, which found that, in 2010, 68.8% of adult smokers wanted to stop smoking, 52.4% had made a quit attempt in the past year, 6.2% had recently quit, 48.3% had been advised by a health professional to quit, and 31.7% had used counseling and/or medications when they tried to quit. The prevalence of quit attempts increased during 2001--2010 among smokers aged 25--64 years, but not among other age groups. Health-care providers should identify smokers and offer them brief cessation advice at each visit; counseling and medication should be offered to patients willing to make a quit attempt.