Mario Rafael Díaz-Balart Caballero ( bə-LART; born September 25, 1961) is an American politician serving as the U.S. representative for Florida's 26th congressional district. A Republican, he was elected in 2002, and his district includes much of southwestern Miami-Dade County, including Hialeah, and much of the northern portion of the Everglades. After Representative Alcee Hastings's death in April 2021, Díaz-Balart became the dean (or longest-serving member) of Florida's congressional delegation.