"A new collective contract, valid until the end of June 2012, has been signed today," the Italian football federation (FIGC) said in a statement.
"The signing followed a meeting in which the legal representatives of the two parties ironed out the final details."
The FIGC said the contract was signed in the presence of its president Giancarlo Abete, Serie A President Maurizio Beretta and AIC President Damiano Tommasi.
The announcement means that Serie A can start on Friday with the meeting of defending champions AC Milan and Lazio, the first round of matches on August 27 and 28 having been called off.
The announcement had been widely expected after the League said last Thursday it was prepared to renegotiate several terms of the contract.
The previous agreement expired at the end of the 2009/10 season and negotiations for its renewal dragged on for the whole of last season.
The AIC said it believed an agreement had been reached in December, when a strike was called off at the last moment, but the Lega Serie A did not sign.
"It's the agreement we reached in December and it's disappointing that the signature has arrived so late, but it was important to have the agreement signed before we played," said AIC President, former Italy international Damiano Tommasi.
"We will play from Friday and I think the players will be given credit for their good sense in this negotiation.
"It [the agreement] is a starting point and I hope it will be a good sign for the next one."
Serie A President Maurizio Beretta said: "It's a profoundly innovative agreement and it was worth our hardline stance because the clubs have achieved much of what they wanted."
The sticking point had been article seven which concerns players who are no longer wanted by their clubs.
The AIC had demanded that the players be allowed to train with the first team until their contracts expired while the clubs wanted the coaching staff to have the power to decide.
