Infante confirmed the deal before Tuesday's game against Washington. He would have been eligible for free agency after the season.
"I want to stay here," he said. "The organization gave me an opportunity to play every day. That's what I want."
Infante said he was looking forward to playing for fellow Venezuelan Ozzie Guillen, who will accept a managerial job with the Marlins for four years, a source close to the situation told ESPNChicago.com's Bruce Levine.
Infante was acquired last offseason in the deal that sent Dan Uggla to Atlanta. Infante went into Tuesday's game batting .279 with seven home runs, 49 RBIs and only eight errors in 146 games.
Information from The Associated Press contributed to this report.