The Brit was rumoured to be in talks with the British WorldTour team, with Ineos officially announcing the news on Friday afternoon (August 21).
In a team press release, Sir Dave Brailsford said: “I’m really delighted that Adam is finally joining the team. It feels like the timing is just right as he enters the prime of his career and we embark on a new era as the Ineos Grenadiers.
“As a global team with a British heart, Adam’s no-nonsense British character is a perfect fit. He knows how to win and his gritty, determined and resilient approach are exactly the attributes we are looking to foster as we assemble the new Ineos Grenadiers to be built on purpose.”
Yates’s move will mean a departure from his twin brother Simon, who this week extended his contract with Mitchelton for another two years.
Adam said: “The prospect of riding for a British team is one that I am extremely excited about.
“I’ve witnessed the rise of cycling in the UK during my career and I think this has been spurred on by success of British riders and this team. It is an exciting opportunity and one that I feel has come at the right time.
Despite following different paths to becoming professionals, the brothers have ridden in the same team at WorldTour level since 2014 when they both stepped up to join Orica Greenedge.
Yates started the year in tremendous form, taking the overall of the UAE Tour, before it was cancelled due to the global pandemic.
The move sees Ineos bring in some fresh British climbing talent to go alongside the likes of Geraint Thomas, with Chris Froome leaving to join Israel Start-Up Nation.
Yates will be joining the team as another general classification leader at the Grand Tours.
While he has no overall wins in the three-week races like his brother Simon, he has won the white jersey for best young rider at the Tour de France along with an assortment of week-long stage races.
The climber continued: “My results in week-long races and one day races have been really solid but I would like to take that consistency to Grand Tour racing with the Ineos Grenadiers and see where it takes me.”