But in a sign of the polarising effect the left-winger has, the poll also found he was the contender rated as having the best chance of improving Labour's fortunes.
Some 21% of those surveyed by ComRes thought Mr Corbyn would improve Labour's chances at the next election, putting him ahead of Andy Burnham on 19%, Yvette Cooper on 15% and Liz Kendall on 11%.
A new poll shows Jeremy Corbyn is the most likely Labour leadership candidate to damage the party's chances at the next election while at the same time he was rated as having the best chances of improving its fortunes
The poll came as a Survation poll on Friday showed that voters would more likely back Labour in an election under Mr Corbyn than any of his leadership rivals. The Islington MP was seven points of his nearest rival, Mr Burnham, on 32%.
The latest poll, for the Independent on Sunday and Sunday Mirror, found 31% of those polled thought Mr Corbyn would worsen Labour's prospects of electoral success - with Ms Cooper on 18%, Ms Kendall on 17% and Mr Burnham on 14%.
The figures gave Mr Burnham a net rating of +5, with Ms Cooper on -3, Ms Kendall on -6 and Mr Corbyn on -10.
None of the candidates performed as well as former foreign secretary David Miliband, defeated by his brother Ed at the last Labour leadership contest - who scored a net rating of +11.
Among Labour voters, some 33% thought Mr Corbyn would improve the party's chances of success at the next election, with 21% saying he would worsen them.
Mr Corbyn, the frontrunner in the contest, would make the state of the British economy worse according to 36% of those surveyed, with just 14% saying it would improve if he was in charge.
Britain's standing around the world would suffer according to 37%, with just 11% thinking it would improve with Mr Corbyn in Number 10.
There was some comfort for Mr Corbyn, who has vowed to take the railways back into public ownership - with 23% believing that the quality of train services would improve compared with 22% who thought they would get worse.
In an indication of the task facing whoever emerges as the winner of the leadership race on September 12, the ComRes study found the Opposition trailing the Tories by 11 points, with David Cameron's party on 40% and Labour on 29%.
Amid growing concern from Labour MPs that Mr Corbyn is on the brink of unlikely victory, former prime minister Gordon Brown is expected to intervene in a speech on Sunday.
The ex-leader, who is held in high regard within the party and credited with a crucial late intervention in the Scottish referendum campaign, will deliver an address on "power for a purpose".
Sources in Ms Cooper's camp have played down reports that Mr Brown is set to endorse her for the leadership, but the shadow home secretary admitted she has spoken to the former prime minister.
"I have spoken to Gordon, I have spoken to lots of different people as part of the campaign, just asking people about their ideas for the future and so on," she said.
ComRes interviewed 2,035 adults in Britain online between August 12 and 13. Data were weighted to be demographically representative of all GB adults and by past vote recall.