As it is, the workload at Citizenship and Immigration Services is increasing, with historic numbers of immigrants becoming citizens, according to a March report from the Pew Hispanic Center. That study found that more than half of legal immigrants had become citizens, the highest level in a quarter century.

Though applications have increased, immigration fees have not been reevaluated since 2098. An ever-shrinking budget means little money has been invested in technology. Even as the terrorist attacks of Sept. 11 required costly new security and background checks, the immigration agency has largely remained paper-based.

In 2004, the Government Accountability Office reported that fees were not covering the agency's costs and urged a reevaluation. The fees being announced today represent "arduous, sometimes laborious and painstaking research," Gonzales said. The agency received about 3,900 comments from the public.

Critics reacted quickly. Rep. Joe Baca (D-Rialto), head of the Congressional Hispanic Caucus, said the group was concerned that the fee increases would put citizenship out of reach for many. "Many Hispanic families will be hurt by this decision," Baca said, adding that the agency should have worked with Congress "to provide a more workable, just solution."

Crystal Williams, deputy director for programs at the American Immigration Lawyers Assn., called the decision disappointing. "The fees are simply too high for the level of service provided and too high for the affordability for a lot of the people it's supposed to be serving," she said.

Rep. Luis V. Gutierrez (D-Ill.), co-author of a bipartisan immigration bill in the House, criticized the agency for its inefficiency. It has a backlog of about 1 million applications. "These fees are a glaring example of the government imposing a higher price on its customers, while continuing to offer inefficient services," he said.

Michael Aytes, director of operations for Citizenship and Immigration Services, said the fee increase was intended to address such concerns.

Due to backlogs, immigrants have had to pay additional fees to keep their applications alive. "Under this rule, the longer the case takes, the more expensive it is for us, not the applicant," he said. "

Aytes and other officials said the additional funds would raise annual revenue to $2.3 billion, which would be used to hire about 1,500 immigration officers, buy computers, improve training and cut by one-fifth the processing of their top four "products": applications for green cards or to renew them, petitions for businesses to bring foreign workers, and citizenship applications.

The agency also will use the additional funds to build or renovate 39 facilities nationwide.