She died in Sant Pau hospital in Barcelona.
The "Gran Teatre del Liceu" opera house in Barcelona, where Caballe performed more than 200 times, described her as "one of the most important sopranos in history".
The star was admitted to hospital because of a gall bladder problem, Spanish media said.
Born to a working-class Catalan family, Montserrat Caballe, who was named after a local monastery, received a first-class musical education. Opera singer Maria Callas is once said to have answered "Only Caballe." when asked once who she considered a worthy successor.
She rose to global fame after a stunning performance as a last-minute replacement for another legend, Marylin Horne, at New York's Carnegie Hall in 1965, and sang in over 80 roles on leading stages around the world. She won the school's Gold Medal on graduating in 1954.
She began in the Swiss city in 1956, as Mimi in La Bohème, then joined the Bremen Opera, where she sang from 1959 to 1962, in a wide variety of roles.
She had stints with the Basel Opera and Bremen Opera before her global breakthrough in 1965 in Lucrezia Borgia at Carnegie Hall in NY. It opened the doors to all the major opera venues around the world.
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He adds: "I'm furious at thinking this has broken out". "I wouldn't go with Zidane", he said on Virgin Media Sport . "Enough is enough for me".
Caballe was also a noted recitalist, particularly of songs of her native Spain.
Her voice was noted for its purity, precise control and power using superb technique and vocal shadings, as well as pianissimos, which were inspired by Spanish operatic tenor Miguel Fleta.
The Spanish opera singer whose song with Freddie Mercury became the featured single of the Barcelona Olympics has passed away.
Queen guitarist Brian May posted a message on Instagram, saying that Caballe was an "inspiration to us all but especially to Freddie".
In 2015, she was convicted of tax fraud and given a suspended sentence of six months in prison.
Maria de Montserrat Bibiana Concepcion Caballe i Folch, has always been considered as one of the greatest sopranos of the twentieth century along with Maria Callas, Joan Sutherland, Kiri Te Kanawa and Jessy Norman. She also established a foundation for needy children in Barcelona.