The Brazilian spent just one season at Stamford Bridge after joining the Blues for a fee in the region of ??16m. It was reported last week that Atletico are paying around ??15m to bring him back
Luis??made his debut as a substitute in the 6-3 win against Everton last August and made his??first start against Schalke in the Champions League before going on to win the Premier League and Capital One Cup.
The 29-year-old has agreed to rejoin Atletico on a four-year contract.
He made 26 appearances for Chelsea in all competitions, scoring one goal, in a Capital One Cup win at Derby.
Of his 26 appearances for Chelsea, only nine of them were starts in the Premier??League as he struggled to displace Cesar Azpilicueta at left-back.
“We wish him all the best for the future,” a club statement read.