Manzano, 65, broke the news earlier this week at the American Library Association Annual Conference. She said she wouldn't be part of PBS' new "Sesame Street" season.
A beloved resident of Sesame Street since she was a teenager, the character Maria owned the neighborhood repair shop with husband Luis (played by Emilio Delgado, who remains on the show).
Manzano also served as a writer for the show, sharing in 15 Emmy awards as a member of the writing team. She has also written children's books.
Born in a Puerto Rican neighborhood of The Bronx that resembled the city world "Sesame Street" would later embrace, Manzano attended Manhattan's High School of Performing Arts and then Carnegie Mellon University in Pittsburgh.
She began her show business career in the original cast of the musical "Godspell," which began as a student production on the Carnegie Mellon campus. She moved up with it as it transferred to a club in New York's Greenwich Village, then to off-Broadway, then Broadway.
In 1971, she auditioned for "Sesame Street," then only 2 years old. As Maria, she and Luis became the masters of repair, including a large quantity of toasters, as co-owners of the Fix-It Shop. Luis and Maria wed in 1988.
In confirming Manzano's retirement, Sesame Workshop said "she will always be a part of the fabric of our neighborhood. During her 44-year career as the iconic 'Maria,' and the first leading Latina woman on television, she was a role model for young girls and women for generations."
Sesame Workshop did not say how her absence would be explained.
Manzano has also performed on the New York stage in productions of "The Vagina Monologues" and "The Exonerated."