His comments came Monday night as the two leading Democratic candidates both raised money in Chicago in the final week of second quarter fund-raising.
A reporter asked Obama about the Clinton campaign touting her experience at recent events.
"The only person who is probably prepared to be President on day one is Bill Clinton, not Hillary Clinton," Obama said. "I think we're all very qualified for the job. The question is who can inspire the nation to move beyond the politics that have bogged us down in the past."
The Illinois senator claimed his candidacy would be stronger at "bridging some of the divides that have blocked progress on health care, blocked progress on energy. That's what we're interested in - not repeating the same old fights but trying to bring about a new consensus that move this country forward."
Meanwhile, former President Clinton sent a fund-raising e-mail Tuesday for his wife's campaign that used the same "day one" phrase. In the message, Clinton wrote, "America is ready for change, and we need a president ready to lead on day one. Ready to end the war in Iraq and restore America's standing in the world." Later in the message, he said, "Hillary is the best candidate for president because she'll stand up for them - she already does every day in the Senate."
A campaign spokesman said the e-mail was pre-planned, and was "absolutely not" a response to Monday night's words. Asked about the Obama remarks, the spokesman said, "no comment."
- CNN Political Desk Managing Editor Steve Brusk