The figure itself comes as no great shock; most news reports in the last couple of years have estimated the budget at $40 billion. But the fact that Ms. Graham would say it in public is a surprise, because the government has repeatedly gone to court to keep the current intelligence budget and even past budgets as far back as the 1940's from being disclosed.

Carl Kropf, a spokesman for the office of the director of national intelligence, John D. Negroponte, said Ms. Graham would not comment. Mr. Kropf declined to say whether the figure, which Ms. Graham gave last Monday at an annual conference on intelligence gathered from satellite and other photographs, was accurate, or whether her revelation was accidental.

Steven Aftergood, director of the Project on Government Secrecy at the Federation of American Scientists, expressed amused satisfaction that the budget figure had slipped out.

"It is ironic," Mr. Aftergood said. "We sued the C.I.A. four times for this kind of information and lost. You can't get it through legal channels."

Only for a few past years has the budget been disclosed. After Mr. Aftergood's group first sued for the budget figure under the Freedom of Information Act in 1997, George J. Tenet, then the director of central intelligence, decided to make public that year's budget, $26.6 billion. The next year Mr. Tenet did the same, revealing that the 1998 fiscal year budget was $26.7 billion.