Quini collapsed while walking near his house in the northern city of Gijon.
Known as “The Wizard,” Quini played in the 1978 and 1982 World Cups with Spain.
His career was also notable for a kidnapping incident during his first year with Barcelona, when he was abducted at gunpoint after a home game, spending 25 days in captivity before being rescued by police.
He played for Barcelona until 1984, making 178 appearances and winning five titles with the Catalan club.
Barcelona said Quini was “a synonym for goals” and “one of the best strikers in Europe in his time.”
Quini spent the majority of his career with Sporting Gijon, who he represented prolifically either side of his 1980 to 1984 stint with Barca.
He won the Pichichi trophy for being the top scorer in La Liga five times and remains eighth on the all-time list in Spain’s top flight thanks to 219 goals across 448 appearances.
His honours at Barca included Copa del Rey triumphs in 1980-81 and 1982-83 – scoring twice against his beloved Sporting in the former final – and the 1981-82 Cup Winners’ Cup.
Barcelona might have completed a Liga and Copa double in 1980-81 but their title bid faltered in astonishing circumstances when Quini was kidnapped at gunpoint after scoring twice in a 6-0 win over Hercules
He was released 25 days later, choosing not to press charges against his captors, and finished the season as La Liga’s top scorer.