Uggla, 30, has 154 home runs in five seasons with Florida. He's a three-time All-Star and just won his first career Silver Slugger award.
Uggla is expected to play second base for Atlanta. His arrival frees up Martin Prado to share time at first base with rookie Freddie Freeman, provides insurance for Chipper Jones at third, and also log some at-bats in left field.
Infante was a first-time All-Star who hit a career-high .321 with eight homers and 47 RBIs. Dunn was 2-0 with a 1.89 ERA in 25 games in his rookie season.
The Uggla trade continues a busy offseason for the Marlins, who dealt outfielder Cameron Maybin to San Diego and sent pitcher Andrew Miller to Boston last week.