The USA Today/Gallup found 26 percent said they would be less likely to vote for Obama after his Wednesday announcement that he supports legalizing gay marriage, compared with 13 percent who said the announcement would make them more likely to vote for him.
The poll found 51 percent of respondents said they supported the president's position on gay marriage to 45 percent who disapproved of it.
Among Democrats, 65 percent said Obama's position would not influence whether they would vote for him, compared with 24 percent who said his position would make them more likely to vote for him and 10 percent who said it'd make them less likely to vote for him.
Among Republicans, 46 percent said the president's stance would have no influence on whether they vote for him, while 52 percent said it would make them less likely to do so and 2 percent more likely to do so.
Among independents, 63 percent said Obama's position would have no influence on whether they vote for him, while 23 percent said it would make them less likely to do so and 11 percent more likely to do so.
Poll results are based on May 10 telephone interviews with a random sample of 1,013 adults 18 and over. The poll has a margin of error of 4 percentage points.