The three-day poll, which ended on Sunday, showed a marginal increase in Biden's popularity from last month, when 40% of respondents said they approved of his performance since taking office in January 2021.
The poll had a margin of error of three percentage points and showed approval of Biden to be largely a matter of partisanship. Some 80% of self-identified Democrats approved of Biden, up marginally from August.
Ninety-one percent of Republicans disapproved of Biden.
Biden's public approval rating has held below 50% since August 2021.
Republican U.S. House of Representatives Speaker Kevin McCarthy on Tuesday called for an impeachment inquiry into Biden, raising the stakes for partisan battle ahead of the 2024 presidential election.
Republicans have accused Biden of profiting while he served as vice president from 2009 to 2017 from his son Hunter Biden's foreign business ventures, though they have not presented substantial evidence. The White House has said there is no basis for an investigation.
Of the four U.S. presidents that preceded Biden, two - Bill Clinton and Donald Trump - were impeached by the U.S. House and acquitted by the U.S. Senate.
Following the Republican-backed impeachment probe into Clinton, a Democrat, Republicans lost House seats in the 1998 midterm elections. Following the two Democrat-backed probes into Trump, the Republican president lost his 2020 reelection bid to Biden.
The new Reuters/Ipsos poll showed the economy remained Americans' top concern, with 23% of respondents selecting it as "the most important problem facing the U.S. today."
U.S. inflation rates have been historically high during Biden's term, prompting central bankers to raise interest rates in a bid to tame prices.
Some 13% of respondents selected "crime or corruption" as the top problem.
The Reuters/Ipsos poll gathered responses online from 1,029 adults, using a nationally representative sample.
(Reporting by Jason Lange; Editing by Scott Malone and Deepa Babington)
