WASHINGTON --- The Senate swiftly approved six members of President Obama's Cabinet on Tuesday but put off for a day the vote on his choice of Hillary Rodham Clinton to be secretary of state.

The Senate confirmed all six with a single voice vote a little more than three hours after Mr. Obama took the oath of office. But Democratic hopes to add Mrs. Clinton to that list were sidetracked when one senator, Republican John Cornyn of Texas, objected to the unanimous vote.

Mr. Cornyn said he still has concerns about foreign donations to the foundation headed by Mrs. Clinton's husband, former President Bill Clinton.

Those confirmed were Steven Chu to be energy secretary, Arne Duncan at education, Janet Napolitano for homeland security, Eric Shinseki to head veterans affairs, Ken Salazar for the Interior Department and Tom Vilsack to lead the Department of Agriculture.

The Senate also approved Peter Orszag, recently the director of the Congressional Budget Office, to head the White House's Office of Management and Budget. Mr. Obama signed nominating papers for his Cabinet picks about an hour after he took the oath.

Senate leaders agreed to have a roll call vote on Mrs. Clinton today after three hours of debate. Jim Manley, a spokesman for Senate Majority Leader Harry Reid, predicted "she will receive overwhelming bipartisan support."

The delayed vote became necessary when Mr. Cornyn objected to the voice vote. In the Senate, a single senator can block measures from being approved by voice.

He said he wanted "a full and open debate and an up-or-down vote on Sen. Clinton's nomination." He said important questions remain unanswered concerning the foundation headed by Mr. Clinton "and its acceptance of donations from foreign entities."

"Transparency transcends partisan politics and the American people deserve to know more," he said.

Cornyn spokesman Kevin McLaughlin said the senator is not trying to block her confirmation, only seeking more debate about the donations.

Several Republicans raised questions at Mrs. Clinton's confirmation hearing about possible conflicts of interest from Mr. Clinton's fundraising work and his acceptance of large donations from foreign countries and companies.

Also left unconfirmed was Timothy Geithner, the nominee to head the Treasury Department. He faces the Finance Committee today, and he will have to explain his initial failure to pay payroll taxes he owed while working for the International Monetary Fund.

The Judiciary Committee is expected to vote as early as today on Eric Holder to be attorney general.