Ayerza, who was already under contract to 2011, has agreed an extension to remain at Welford Road beyond the Rugby World Cup.
Since joining the club from the Cardinal Newman club in Argentina during the summer of 2006, Ayerza has won three Premiership titles with Tigers and played in two Heineken Cup Finals.
Named in the Sky Sports Dream team in 2008/09, he has made more than 100 appearances in Leicester Tigers colours and has 29 caps for Argentina.
Tigers director of rugby Richard Cockerill said: “Marcos has developed as a player with every season he has spent with us and I’m delighted that he has agreed an extension to his contract.
“He is a top-class operator and he is among our senior core of players now.”
Ayerza, 27, said: “I am entering my fifth season with Leicester Tigers and this is a great place to play your club rugby. We have an excellent group of players, there is a great spirit here and I hope we can start the new season well and I’m looking forward to it.”