Broxton, 28, was 3-3 with a 2.82 earned run average and four saves after joining the Reds in July in a trade with the Kansas City Royals. He is expected to be the Cincinnati closer as Aroldis Chapman is penciled into the starting rotation next season.
Broxton has pitched eight seasons in the major leagues, building a 29-25 record with a 3.10 ERA and 111 saves. He broke into the majors with the Los Angeles Dodgers in 2005 and played seven seasons with the Dodgers before signing a free agent contract with Kansas City last November.
The new deal with Cincinnati includes a $9 million option and a limited no-trade clause.