Armstrong plans include riding in the 2010 Tour de France
Seven-time Tour de France champion Lance Armstrong will quit Astana and form a US-based team for 2010.
The new outfit will be known as Team RadioShack and sponsored by the American electronics retail giant.
Armstrong said: "To compete for an American team with the world's top cyclists, supported by the best coaches and staff - I couldn't be happier."
The Texan returned to competition with Astana after a four-year retirement and lies third overall in this year's Tour.
In a statement, the RadioShack Corporation said: "Lance Armstrong will compete for Team RadioShack as a cyclist, runner and triathlete in events around the world, including the 2010 Tour de France."
Earlier this year, doubts over the financial situation of Astana - which is bankrolled by an arm of the Kazakh government - led to fears the team would be barred from the Tour.
Armstrong's Astana manager Johan Bruyneel, who guided him to his seven Tour wins, has made it clear he will be leaving the team after this season.
Armstrong, who successfully battled cancer in 1998 to return to cycling and win the first of seven consecutive yellow jerseys in 1999, said the fight against the disease through his Livestrong Foundation would remain a priority.
"This has been a great season so far - the response in the countries we've been to has been amazing and it's clear now that this was the right choice," he said.
"Utilising the massive media attention that the sport receives has been the perfect vehicle to help spread the Livestrong message around the world.
"We have an incredible opportunity to leverage RadioShack's connection to tens of millions of people to spread the Livestrong message."
RadioShack's chief marketing officer Lee Applbaum said: "As one of the greatest athletes of our generation, a father, a cancer survivor, and a tireless advocate in the fight against cancer, Lance understands the power of keeping people connected, and that's why we feel he's the perfect partner for our brand."
The announcement was made immediately after the 18th stage of the Tour de France, won by Armstrong's Astana team-mate and race leader Alberto Contador.
Asked whether he would be part of the project, the Spaniard, who has not always seen eye-to-eye with Armstrong, said: "I heard that Lance was launching a new structure. But I just want to concentrate on winning the Tour and we'll see afterwards."
Armstrong's new team have submitted an application to the International Cycling Union (UCI) for a ProTour licence, which is needed to race in road racing's top events.
UCI president Pat McQuaid said: "They delivered it to us on Monday, it then goes through a process of evaluation and eventually the license commission takes a decision based on a variety of criteria."