Rueda, 60, replaces Ze Ricardo, who was fired earlier this month after a string of poor results that included Flamengo's elimination from the Copa Libertadores.
The club are currently in seventh place of the Brazilian first division.
Rueda, who has coached Colombia, Ecuador and Honduras in addition to several clubs in his homeland, last year took Medellin's Atletico Nacional to the finals of both the Libertadores and the Copa Sudamericana, South America's equivalent of the Europa League.
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(Reporting by Andrew Downie; Editing by Gareth Jones)
