REUTERS/Chris Aluka Berry
Just 32% of Americans viewed the GOP favorably - the lowest that rating has been since the poll's inception in 2009.
The Democratic Party's favorability rating was notably higher, at 49%.
Pollster J. Ann Selzer linked the low GOP rating to Donald Trump, the presumptive party nominee for president.
"This is obviously related to perceptions of Trump," Selzer told Bloomberg. "This bleeds out into perceptions of the party and to other GOP politicians."
While nearly 33% of Republicans said they viewed Trump unfavorably, only 17% of Democrats had an unfavorable view of Hillary Clinton, the presumptive Democratic presidential nominee.
Negative feelings about the GOP are also increasingly coming from within the party's own membership. In December 2014, 9% of Republicans viewed the party unfavorably. That number has now climbed to 28%.
But Trump still has significant support from party members. The Bloomberg poll found that 69% of likely Republican voters think Trump will be good for the party.
Bloomberg's poll was conducted Friday through Monday. It had a margin of error of plus or minus 3.1%.
Another Bloomberg poll released Tuesday showed Trump trailing Clinton by a whopping 12 points in a general election matchup.
And an overwhelming 55% of total respondents said that they could never support Trump. In comparison, 43% of those polled said that they could never support Clinton.
The Bloomberg poll was the third such survey this week to show Clinton with a commanding lead.
An NBC/SurveyMonkey weekly tracking poll released on Tuesday morning showed Clinton with a seven-point lead over Trump, a four-point bump over NBC's tracking poll two weeks ago.
And a Washington Post/ABC poll released Tuesday found Trump's negative rating at its highest level of any time since he entered the presidential campaign almost exactly one year ago. That poll found that 70% of Americans hold a negative view of Trump, compared to 55% who hold a negative view of Clinton.
Allan Smith and Maxwell Tani contributed to this report.