24 Hour Fitness has 330 sports club in the US, and sponsors seven sporting governing bodies, including USA Cycling.
The fitness chain will also become a sponsor of Armstrong's Discovery Channel cycling team.
Lance will lend his face to a 24 Hour Fitness advertising campaign later in the year.
"Lance Armstrong embodies everything our company believes in - hard work, determination, positive attitude and persistence while having fun along the way," said Mark Mastrov, chairman and CEO, 24 Hour Fitness Worldwide.
Armstrong will put his own "signature" on the look, feel and facilities of the new 24 Hour Fitness Lance Armstrong Sport Clubs. The clubs will include large Lance Armstrong indoor cycling rooms.
Armstrong said: "I really believe in the work 24 Hour Fitness is doing to help as many people as possible through health and fitness. They fight the good fight and truly care about their members' lives. Fitness has been a significant part of my life and a critical component in my comeback from cancer."