Gardai in Galway i have recovered the head of the limestone statue of the writer, Padraic O Conaire.
It is understood it was damaged some time during Thursday night or early Friday morning in well-lit Eyre Square.
The hunt for the missing head began shortly before midday yesterday when gardai were informed of the decapitation by the city's mayor, Cllr Angela Lupton.
In an emotional appeal for the head's return yesterday, she said: "Someone must have seen something.
"This is Galway's most famous landmark, and it is heartbreaking to see what has happened," Ms Lupton said.
The statue, which was designed by Albert Power and unveiled in the square by the late Eamon de Valera in 1935, was due to be moved as part of a proposed redesign of the square which includes a sculpture park.
Mr Peadar O'Dowd, president of the Galway Archaeological and Historical Society, referred to the damage as "the greatest cultural outrage in the west of Ireland".
It is the second attack on the statue of the author of M'Asal Beag Dubh in 10 years. His work has been compared to that of the Russian dramatist and short-story writer, Chekhov.
In the first "assault", his hat was chipped and had to be repaired by Galway Corporation. Even before the statue was commissioned, it was the subject of some controversy, due to O Conaire's reported penchant for alcohol.
Bemused tourists posed for photos behind the headless statue yesterday, as city-dwellers expressed shock and dismay at the occurrence. One passer-by put a brave face on it, referring to last year's beheading of the Little Mermaid in the Danish capital of Copenhagen.
"At least it will bring us some publicity, and sure we were taking him for granted anyway," he said.
The Little Mermaid has since been restored to full bronze glory on Copenhagen's waterfront, following her second decapitation in 34 years.
Padraic O Conaire was born in Galway in 1882. His parents died when he was young and he was brought up in Connemara by his grandparents.
After his education in the Connemara Gaeltacht, Rockwell and Blackrock College, he joined the civil service in London and began to write. He published a play, a novel and a number of short stories.
Continuing to write in Irish, he left the civil service in 1914 and wandered in Ireland. He published another novel, collections of essays and further short stories.
M'Asal Beag Dubh, essays on the delights of open-air life, was reprinted several times. He published more than a dozen books, including Seacht mBua an Eiri Amach, An Crann Geagach, Siol Eabha, Beagnach Fior, and Fearfeasa Mac Feasa.
He spent his final years teaching Irish in Galway and died in the Richmond Hospital, Dublin, in 1928. His only possessions when he died were his pipe and tobacco and an apple.
