The contract with Gremio, who comes from Porto Alegre in southern Brazil, extends over two years.
The 35-year-old striker joins Gremio from Uruguayan side Nacional.
There he accounted for eight goals in 14 games and won the Uruguayan league title.
Suárez was part of the Uruguayan national team that was eliminated in the group stage of the World Cup in Qatar.
Suárez has previously played in Liverpool, Barcelona and Atlético Madrid, among others.
With Barcelona, he won the Champions League in 2015 and La Liga four times.
MORE FOOTBALL: Lowered after ten seconds - then Erling Haaland replied
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Was lowered after ten seconds - then Erling Haaland answered Photo: Bildbyrån