A CBS News poll of 473 uncommitted voters found that 46 percent said Biden won the debate, while 21 percent said Palin, Republican nominee John McCain's running made, won. Thirty-three percent of those polled said the debate was a tie.
After watching the debate, 18 percent of the previously uncommitted voters said they would vote for Democrats Barack Obama and Biden, while 10 percent said they plan to support John McCain and Palin.
Seventy-one percent of those polled said they are still uncommitted.
The CBS poll also found that 66 percent of uncommitted voters see Palin, the Alaska governor, as knowledgeable about the issues, up from 43 percent before the debate in St. Louis. By comparison, 98 percent said they saw Biden, the senior senator from Delaware, as knowledgeable, up from 79 percent before the debate.
The poll's margin of error was not reported.