His selections include longtime advisers and a onetime political foe. Most notably, Democratic primary rival Hillary Rodham Clinton will be named secretary of state and President Bush's defense secretary, Robert Gates, will stay in his current post. The two were among six whom Obama planned to announce at a news conference in Chicago, Democratic officials said.

The officials said Obama also planned to name Washington lawyer Eric Holder as attorney general and Arizona Gov. Janet Napolitano as homeland security secretary. He also planned to announce two senior foreign-policy positions outside the cabinet: campaign foreign-policy adviser Susan Rice as U.N. ambassador and retired Marine Gen. James L. Jones as national security adviser.

The Democratic officials disclosed the plans yesterday on a condition of anonymity because they were not authorized for public release ahead of the news conference. Those names had been discussed before for those jobs, but the officials confirmed that Obama will make them official today in his hometown.

Obama also has settled on former Senate Democratic leader Tom Daschle to be his secretary of health and human services and New Mexico Gov. Bill Richardson to be commerce secretary, but those announcements are not yet official. Last week, he named members of his economic team, including Timothy Geithner, president of Federal Reserve Bank of New York, as treasury secretary.

The decisions mean Obama has half of his cabinet assembled less than a month after the election, including the most prominent positions at the State, Justice, Treasury and Defense Departments.

Clinton's nomination is the latest chapter in what began as a bitter rivalry for the Democratic presidential nomination. After Obama defeated her, Clinton backed his general-election campaign against Republican Sen. John McCain, and she now has agreed to give up her Senate seat to be his top diplomat.

To make it possible for his wife to become secretary of state, party officials said, former President Bill Clinton agreed to:

Disclose the names of every contributor to his foundation since its inception in 1997 and of all future contributors.

Refuse donations from foreign governments to the Clinton Global Initiative, his annual charitable conference.

Cease holding CGI meetings overseas.

Volunteer to step away from day-to-day management of the foundation while his wife is secretary of state.

Submit his speaking schedule to review by the State Department and White House counsel.

Submit any new sources of income to a similar ethical review.

"It's a big step," said Sen. Richard G. Lugar of Indiana, the top Republican on the Senate Foreign Relations Committee, who said he planned to vote to confirm Clinton.

Lugar said there would still be "legitimate questions" raised about the former president's extensive international involvement. "I don't know how, given all of our ethics standards now, anyone quite measures up to this who has such cosmic ties, but . . . hopefully, this team of rivals will work," Lugar said.

Also yesterday, Vice President-elect Joseph R. Biden Jr. said he had chosen a close adviser of more than 25 years as his counselor and had picked two other longtime political advisers for key posts.

Michael C. Donilon, who was part of Biden's debate-preparation team and served as his traveling adviser during the general-election campaign, was named counselor to the vice president. Donilon has worked as a strategist on numerous political campaigns, including Douglas Wilder's successful campaign for Virginia governor in 1989 and Bill Clinton's presidential campaign in 1992.

Terrell P. McSweeny will serve as domestic-policy adviser to the vice president, according to a statement from Biden's office. She was Biden's deputy chief of staff and policy director in the Senate, where she managed domestic and economic policy development and legislative initiatives, and was his issues director during the general-election campaign. She has advised three presidential candidates, including Wesley Clark and Al Gore.

Evan M. Ryan will be assistant to the vice president for intergovernmental affairs and public liaison. She was an adviser to Biden during the general-election campaign and was his deputy campaign manager during the primary.

Ryan worked on the White House staff from 1994 to 2000, as special assistant to first lady Hillary Rodham Clinton's chief of staff, then as deputy director of scheduling.