Some mourners sobbed, while others shouted their thanks, clapped, danced, sang and threw flowers to honor the famed singer, who was known by the nickname "La Negra" for her jet-black hair.
A funeral procession accompanied Sosa's body to the La Chacarita cemetery from the National Congress building, where it had laid in repose for a non-stop flow of fans and mourners who came to pay their respects.
The cemetery is also the final resting spot for famed tango singer Carlos Gardel.
"Mercedes will live on and endure. She has left a great emptiness, but also the best memories of her virtues," said Jose Bermudez, 54.
Legendary footballer Diego Maradona paid tribute to Sosa, saying "one of the all time greats is dead" and calling her a "goddess of freedom."
A militant communist, Sosa went into exile in Europe during the Argentine military dictatorship from 1976 to 1983.
Crowds of fans who had gathered to bid the folk singer farewell, sang and danced the traditional South American zamba, clapping and waving scarves to the sound of guitars and drums.
After a prayer service, Sosa's cortege began its final journey to the cemetery, where her remains were cremated.
Sosa died in her hospital bed "at peace," according to Fabian Matus, her only son.
"Welcome to eternity," said Leon Gieco, a famous singer and one of Sosa's close friend, during a concert Monday in Tucuman, the Argentine province where the folk legend was born.
Television stations carried images of the funeral to the strains of one of Sosa's best known songs "Gracias a la Vida," or "Thanks to Life."
Gracias a la Vida
(Lyrics by Violeta Parra)
Lyric (English Translation)
Mercedes Sosa - Thanks to life
(written by Violeta Parra)
Thanks to life, which has given me so much.
It gave me two beams of light, that when opened,
Can perfectly distinguish black from white
And in the sky above, her starry backdrop,
And from within the multitude
The one that I love.
Thanks to life, which has given me so much.
It gave me an ear that, in all of its width
Records— night and day—crickets and canaries,
Hammers and turbines and bricks and storms,
And the tender voice of my beloved.
Thanks to life, which has given me so much.
It gave me sound and the alphabet.
With them the words that I think and declare:
"Mother," "Friend," "Brother" and the light shining.
The route of the soul from which comes love.
Thanks to life, which has given me so much.
It gave me the ability to walk with my tired feet.
With them I have traversed cities and puddles
Valleys and deserts, mountains and plains.
And your house, your street and your patio.
Thanks to life, which has given me so much.
It gave me a heart, that causes my frame to shudder,
When I see the fruit of the human brain,
When I see good so far from bad,
When I see within the clarity of your eyes...
Thanks to life, which has given me so much.
It gave me laughter and it gave me longing.
With them I distinguish happiness and pain—
The two materials from which my songs are formed,
And your song, as well, which is the same song.
And everyone's song, which is my very song.
Thanks to life
Thanks to life
Thanks to life
Thanks to life
The song is from a 1972 album that honored the late Chilean poet and singer Violeta Parra with interpretations of some of her poems.
Sosa was one of the leading exponents of the "Nueva Cancion," a musical style that combined ballads with folkloric instruments, with lyrics that often combined romantic themes and social issues.
During a long career that saw her produce 40 albums, Sosa collaborated with musicians ranging from Luciano Pavarotti, Sting and Joan Baez to Latin stars such as Shakira, Caetano Veloso and Joan Manuel Serrat.
"She had the greatest voice, and she had the greatest heart for understanding suffering," Shakira said in a statement through her Bogota office.
Sosa "was the voice of her brothers on Earth who lifted up the music of suffering, and of justice," Shakira said.
Sosa performed in the Sistine Chapel at the Vatican in 1994, and to sold-out crowds at Carnegie Hall in New York in 2002 and at the Coliseum in Rome along with piano legend Ray Charles in 2002.