The Field Poll also found that the state's troubled economy dominates voter concerns, and that a majority of likely voters disapprove of the law Democratic Gov. Gray Davis signed allowing illegal immigrants to obtain driver's licenses.
Experts had expected GOP front-runner Arnold Schwarzenegger to absorb most of the 5 percent support held by Ueberroth. But the poll showed Schwarzenegger and Lt. Gov. Cruz Bustamante each picked up 2 percentage points with Ueberroth out of the mix.
In other developments:
Ueberroth, a Republican businessman and chief of the 1984 Los Angeles Olympic Games, withdrew Tuesday, saying that his campaign never captured strong voter interest.
The poll, conducted over five days ending Sunday, has a margin of error of plus or minus 4.5 percentage points and was drawn from phone interviews with 505 likely voters.
Mark DiCamillo, director of the Field Poll, said his staff was easily able to revise results after Ueberroth's announcement because voters had been asked for both their first and second preferences in the event one candidate dropped out.
Bustamante, a Democrat, went from 30 percent with Ueberroth in the race to 32 percent with him gone. Schwarzenegger went from 25 percent of the vote to 27 percent.
Republican state Sen. Tom McClintock, a conservative, took the final slice of Ueberroth's supporters, going from 13 percent to 14 percent.
"Intuitively, you would think that if a Republican drops out of the race that the leading Republican would benefit," said Mark DiCamillo, director of the Field Poll. "But because of the unique nature of Ueberroth's support, we see it spread among three candidates — including a Democrat."
The new poll also found that economic worries dominate voter interest.
When considering where candidates stand, the economy, public schools and the state budget were at the top of the list of issues voters deemed very important.
Ueberroth declined to endorse any candidate.
Schwarzenegger has the support of many Republican leaders who believe he offers the party its best chance of winning. Many of his backers want McClintock to drop out so that Republicans avoid splitting their vote and handing the contest to Bustamante.
But McClintock dug in his heels Tuesday and called on Schwarzenegger to debate him at this weekend's California Republican Party convention in Los Angeles.
"Let Arnold tell the convention what besides celebrity and money does he have to offer," the release said. "We know he can play the role of governor. We do not know if he can be a real governor."
Schwarzenegger's campaign said the actor would stick with his plan of engaging in only one candidate debate, on Sept. 24 in Sacramento. Candidates are getting the questions for that debate in advance.
Ueberroth is the latest Republican to drop out of the race to replace Davis in the Oct. 7 election. Businessman Bill Simon and U.S. Rep. Darrell Issa, who financed the recall effort, both exited as their poll numbers remained low and party leaders urged a slimmer field.
Simon's and Ueberroth's names will still be among the 135 on the ballot because they dropped out too late to remove them. Issa never filed candidacy papers.