Marshall was traded to the Chicago Bears on March 13, 2012, for one third round draft pick in 2012 and a future one in 2013, reuniting him with former Bronco teammate Jay Cutler leading to a career year for Marshall. In his Bears debut against the Indianapolis Colts, Marshall caught 9 passes for 119 yards, which was the twentieth time he surpassed one hundred yards in his career. He also caught a 3-yard touchdown pass, as the Bears would go on to win 41–21. After the Bears win over the Detroit Lions in Week 7, Marshall was fined $10,500 for wearing orange cleats. In Week 12 against the Minnesota Vikings, Marshall recorded 12 catches for 92 yards, and passed the 1,000 yards receiving mark in a season for the sixth time in his career, making Marshall the first Bears receiver to accomplish the feat since Marty Booker in 2002. Two weeks later against the Vikings, Marshall recorded ten catches for 160 yards, passing Booker's single season reception mark with a total of 101 receptions. In Week 16 against the Arizona Cardinals, Marshall broke Marcus Robinson's single-season franchise record for receiving yards set in 1999. On December 26, Marshall was named to the 2013 Pro Bowl, making him the second Bears receiver to be named to the game since Dick Gordon in 1971, with the first being Booker in 2002. However, Marshall did not play in the game due to having an arthroscopic procedure on his hip, and was replaced by Larry Fitzgerald. Marshall finished the season with 118 receptions, 89 catches more than the next Bears receiver Earl Bennett, tying the New England Patriots receiver Wes Welker for second, behind Detroit Lions' Calvin Johnson, and third in receiving yards with 1,508, behind Houston's Andre Johnson.