Atletico youth product Lopez, 30, left the Vicente Calderon after over a decade in the first team, having lost his place to Filipe Luis and the captaincy to Alvaro Dominguez.
"Antonio Lopez has reached an agreement with the club to be their first signing of the 2012-13 season," the club said on their official website.
"The 30-year-old defender will sign for two seasons with the option of another and will be presented this afternoon at the Iberostar stadium."
Lopez made 343 first-team appearances for Atletico, and spent two seasons on-loan at Osasuna earlier in his career.
He made 16 appearances for Spain between 2005-07.