Buenos Aires Mayor Horacio Larreta Rodriguez unveiled the statue on the shores of the River Plate on Paseo de la Gloria (Glory Street), which already boasts statues of other famous Argentine sports starts such as tennis player Gabriela Sabatini and basketball player Manuel Ginobili.
Messi made the announcement following Argentina's defeat by Chile in the Copa America final.
Since then, there has been an outpouring of support for the player.
Argentines have been using social media to ask the 29-year-old to reconsider his decision under the hashtag #NoTeVayasLio (Don't go, Lio).
Among those trying to convince Messi to stay was President Mauricio Macri.
He has been very successful at club level as well and has also been awarded the Ballon d'Or five times.