"No, I don't think it's a good idea," Pelosi said in an interview with CNN talk show host Larry King aired Thursday night.
"I think first of all the candidate, whoever he or she may be, should choose his or her own vice presidential candidate," said Pelosi, who will chair the Democratic National Convention in Denver in August. "I think that's appropriate. That's where you would see the comfort level on not only how to run, but how to govern the country.
"And there's plenty of talent to go around to draw upon for a good, strong ticket. I'm not one of those who thinks that's a good ticket."
But Pelosi added that if Clinton and Obama "think that it's a good ticket, maybe it is. But I don't think that we should thrust the vice presidential choice onto the presidential nominee. That's her or his decision to make."
Pelosi also said she agrees with Democratic National Committee chairman Howard Dean that the nomination should be settled before the national convention.
"I don't want a brokered convention. I think there's too short a time — maybe just about eight weeks between the end of the convention and the election. And I don't think that's enough time to bring everyone together," Pelosi said.
"I do think that the campaigns have to work their way through this, that we should have all the elections, let the people speak and then we'll find out who our nominee is."
The last Democratic primaries are June 3 in Montana and South Dakota.