Rudolph W. Giuliani has been broadcasting radio advertisements in Iowa and other states far from the city he once led stating that as mayor of New York, he “turned a $2.3 billion deficit into a multibillion dollar surplus.”

The assertion, which Mr. Giuliani has repeated on the trail as he has promoted his fiscal conservatism, is somewhat misleading, independent fiscal monitors said. In fact, Mr. Giuliani left his successor, Michael R. Bloomberg, with a bigger deficit than the one Mr. Giuliani had to deal with when he arrived in 1994. And that deficit would have been large even if the city had not been attacked on Sept. 11, 2001.

“He inherited a gap, and he left a gap for his successor,” Ronnie Lowenstein, the director of the city’s Independent Budget Office, a nonpartisan agency that monitors the city budget, said of Mr. Giuliani. “The city was budgeting as though the good times were not going to end, but sooner or later they always do.”

The Giuliani campaign defended the advertisement, noting that it merely states that Mr. Giuliani created a multibillion-dollar surplus, not that he passed one on to his successor.