Carlos Agustín Mármol (born October 14, 1982, in Bonao, Dominican Republic) is a relief pitcher in Major League Baseball for the Chicago Cubs. As of August 24, Mármol is the Cubs closer.

Mármol started his career as a catcher/outfielder. In his last season as a hitter, in 2002, he batted .258 with a .271 OBP for the Arizona Cubs in the Rookie League, and .149 with a .167 OBP for Lansing in the Low A League.

After batting .273 in 14 minor league games, Mármol converted to become a pitcher. He went 26-19 with a 3.41 ERA before being called up to the majors and being added to the major league roster in November 2005.