U.S. Senator and presidential candidate Barack Obama says he is not interested in running for vice president.

The Democratic candidate spoke Monday evening during an appearance on Late Night With David Letterman,a late night television talk show.

During the show, Obama dismissed the idea that he might consider sharing a ballot with Democratic Senator Hillary Rodham Clinton, telling host David Letterman that "you don't run for second." When Letterman suggested the two senators would make a powerful ticket running together, Obama drew laughter from the audience by replying "Which order are we talking?"

The first term Illinois Senator made news last week when he announced that he has raised more than $25 million this year for his campaign.

Clinton, who has been the Democratic party's front-runner, has raised $26 million so far this year.

Former Senator John Edwards is another prominent Democratic candidate in the race for the 2008 election.

Some information for this report was provided by AP and Reuters.