The price, paid by a telephone bidder, was almost six times the highest
pre-sale estimate.
The iconic garment had been expected to fetch between $98,000 and
$138,000 as part of a sale of film and television memorabilia at Christie's auction
house in London.
Proceeds from the sale will go to the charity City of Joy Aid, which
helps India's poor.
Hepburn wore the dress for one of her best-known roles, as eccentric
Manhattan socialite Holly
Golightly in the 1961 film adaptation of Truman Capote's novel.
The opening scenes of the film show Golightly in the dress emerging
from a taxi on 5th Avenue with her brown-bag breakfast to ogle diamonds
and luxury goods in the storefront windows of Tiffany & Co.
Images of Hepburn dressed as Golightly - with gloves, an elaborate
pearl choker and trademark cigarette holder- still endure.