While his favorable rating has declined from 54 percent to 44 percent in the six-month span, his unfavorable rating has ballooned, from 27 to 45 percent.
Bush has been hit the hardest by a 39-point decline in support among Republican men, the poll found.
While conservative males once viewed Bush favorably by a plus-30 margin, the group now views him unfavorably by a minus-9 spread.
Bush’s minus-1 rating is also good for last place in the Republican primary field.
Sen. Ted Cruz (R-Texas) is seen as the most favorable candidate, with a net favorability rating of plus-45, followed by Ben Carson at plus-40, and Sen. Marco Rubio (R-Fla.) at plus-35.
Donald TrumpDonald TrumpTrump slams 'totally biased' judge in Trump U case Ex-pharma CEO Martin Shkreli: I didn’t endorse Trump Five things Clinton needs to do to win the California primary MORE, who has led national polls in the primary race for several months, has a net favorability of plus-24. He is the only candidate within 10 points of Bush’s unfavorable rating, with 35 percent of Republicans viewing him negatively.
Republican voters’ unfavorable impression of Bush has also been reflected in national polls.
According to a RealClearPolitics average poll, Bush has just 3.3 percent support nationwide in the GOP primary.
The Gallup poll is an accumulation of telephone surveys conducted between July 8 and Jan. 5. The survey polled 44,111 Republicans and Republican-leaning independents over that timeframe and has a margin of error of 4 percent.