She urged smokers to take part in the Great American Smokeout Thursday by giving up smoking at least for the day.
Sebelius called tobacco use, responsible for more than 440,000 deaths a year in the United States, the leading preventable cause of death in this country.
"Our nation has made great strides in the fight against tobacco," Sebelius said in a statement.
"In fact, our nation now has more former smokers than current smokers. But our smoking rates are still too high: 20.6 percent of adults and 19.5 percent of high schoolers smoke," she said.
"But help is out there: Anyone can pick up the phone and call 1-800-QUIT-NOW and get expert assistance. Another resource is http://www.smokefree.gov."
"And thanks to our recently passed Affordable Care Act, many health plans will cover the costs of medication and counseling to help people quit," Sebelius said.