Italian artist and sculptor Maurizio Cattelan created the fully functional 18-carat gold lavatory, which he has titled America.
The, ahem, interactive exhibit has been installed in one of the Guggenheim's public bathrooms, reports the New Yorker.
The Fifth Avenue museum describes the piece as "a bold, irreverent work".
The lavatory replaced one of the Guggenheim's porcelain toilets in a one-person, unisex restroom.
Visitors who pay museum admission will be able to use it as they wish.
The Guggenheim said the piece is "ultimately reminding us of the inescapable physical realities of our shared humanity".
The exhibit is aimed at "making available to the public an extravagant luxury product seemingly intended for the 1 percent", according to the museum.
"Its participatory nature, in which viewers are invited to make use of the fixture individually and privately, allows for an experience of unprecedented intimacy with a work of art," said the Guggenheim.
Cattelan, a Milan-based artist and a truck driver's son, hinted earlier this year that his creation had been inspired by economic inequality.
The exhibit has also drawn comparisons with Marcel Duchamp's avant-garde "Fountain", the porcelain urinal he exhibited in New York in 1917, causing a sensation in the art world.
Cattelan, 55, is known for his provocative sculptures, including La Nona Ora (The Ninth Hour), which depicted Pope John Paul II floored by a meteorite.
Members of the public are being invited to spend a penny in a solid gold toilet at New York City's Guggenheim Museum.