Diaz-Balart said he would return to practice law "with a sense of duty fulfilled" after leaving the House when his term expires in January 2011, The Hill reported.
At one time, Diaz-Balart was thought to be a possible Senate appointee last year when Sen. Mel Martinez, R-Fla., resigned.
If he chooses to pursue his brother's seat, Rep. Mario Diaz-Balart, R-Fla. would be moving to a more Republican district, and would leave a seat that could be more susceptible to a Democratic takeover, the Washington publication said.
Lincoln Diaz-Balart was elected to the House in 1992 and, in 1994, was the first Hispanic named to the Rules Committee, his Web site said. He is chairman of the Congressional Hispanic Leadership Institute.