Gormley – who is best known for his Angel of the North Sculpture – created the cover more than a decade ago for a street in Peckham.
The cover was designed around the artist’s feet and remained anonymously on the south London street until last week when a local blogger highlighted it online.
Ian Mansfield of ianvisits.com said: “A few days ago, I wrote about a manhole cover in South London — not just any manhole cover though, for this is a work of art by celeb-artist Antony Gormley.
“A few people joked that now I had written about it, someone would steal it.
“Sadly, jokes have become reality, as at some point on Tuesday night, miscreants chose to manhandle the manhole cover and make off with its man inspired design.”
Thames Water said the designer cover has now been replaced with a standard manhole.