Fifty-three percent of registered voters would be less likely to vote for a candidate endorsed by the former Alaska governor, said The Field Poll conducted for The Riverside Press-Enterprise and other California media.
Twenty-one percent said they would be more inclined to vote for a Palin-backed candidate and 26 percent expressed no opinion or said it would not matter.
Palin is scheduled to campaign for Republicans next week in Anaheim.
"The advantage you get from Republicans is more than offset by the disinclination you get from Democrats and non-partisans," Field Poll Director Mark DiCamillo said. "She's just a very polarizing figure."
Among independent voters, 69 percent have an unfavorable impression of Palin, with 25 percent seeing her positively.
The poll included responses from 414 registered voters and has a 4.9 percent margin of error.
A Field Poll released last week found 40 percent of voters would be less likely to vote for a candidate endorsed by President Barack Obama.