Former Liverpool midfielder Leiva retires at 36 due to heart condition
The 36-year-old played nearly 600 games in his club career, the majority in Europe having signed for Liverpool in 2007, before moving to Italy's Serie A in 2017, where he played five seasons with Lazio.
Leiva returned last summer to his boyhood club Gremio, making 17 appearances and scoring three goals for the Brazilian side before being sidelined in December, when he was diagnosed with the heart issue after routine tests.
"I would like to thank Gremio for all the support in these three months. Today I am announcing my retirement. It's been a difficult period," Leiva told a news conference.
"I'm ending where I'd like, not the way I'd like. But I'm sure a new cycle will begin. I had a lot of hope that it could reverse, but it was not the case. My health comes first."
The Brazilian, who won the South American under-20 championship in 2007, also earned 24 international caps.