The 31-year-old is yet to sign a contract with the Serie A side, who finished fourth in the 2012-13 season to qualify for the Europa League, while no financial details of the agreement have been released.
A statement published on violachannel.tv read: "Fiorentina and Malaga have reached an agreement for the outright transfer of Joaquin Sanchez Rodriguez, subject to the player signing a contract."
Joaquin scored eight goals in 45 appearances in all competitions for Malaga last season and represented Spain 57 times in a five-year spell with the national side.
A right-sided winger noted for his pace and dribbling ability, he played over 200 league games for boyhood Real Betis before moving to Valencia in 2006.
He won the Copa del Rey with Los Che two years later and, after joining Malaga in 2011, he played a key role as the Boquerones reached the quarter-finals of last season's Champions League.
And Malaga, who yesterday lost their appeal against a one-year ban from European competition, wished the player well with a statement on their official website.
It read: "Malaga would like to thank Joaquin for his dedication, professionalism and commitment to the club and wishes him luck in his first professional experience outside of Spain."