The Liberal Democrats have held Cheadle in a parliamentary by-election.
Mr Hunter (right) won with a majority of 3657
The election was triggered by the death of Lib Dem MP Patsy Calton from cancer shortly after May's general election.
Mark Hunter held the Greater Manchester seat for the Lib Dems with 19,953 votes, a 3,657 majority over Tory candidate Stephen Day, who came second.
Mr Hunter said people had voted for a "more honest and positive approach". Labour's Martin Miller came third with 1,739 votes but lost his £500 deposit.
The swing was 0.63% from Conservatives to Liberal Democrats - Mr Miller lost his deposit because he won less than 5% of the vote.
The outcome will come as a relief to Lib Dem leader Charles Kennedy, who has been criticised by some elements in the party since the election.
He is due to visit Cheadle later on Friday to celebrate the victory.
Mr Kennedy said: "This is a first class victory for the Liberal Democrats.
CHEADLE VOTE STATISTICS
Mark Hunter (Lib Dem) 19,593 (52.15%, +3.27%)
Stephen Day (Tory) 15,936 (42.42%, +2.01%)
Martin Miller (Labour) 1,739 (4.63%, -4.16%)
Leslie Leggett (Veritas) 218 (0.58%)
John Allman (Alliance for Change - Suffering Little Children) 81 (0.22%)
"It is further proof that British politics is now three party politics - with the Lib Dems as a growing force for the future."
He told BBC Radio 4's Today programme the party had "fought the seat very hard" - but this was normal for a by-election and not the result of fears that losing the seat might cost him his leadership.
Mr Kennedy was recently re-elected unopposed as party leader. He denied reports he had warned his frontbenchers he would sack anybody trying to destabilise his leadership.
"I said no such thing," he said, although he had told colleagues not to be distracted by press reports from Westminster which were "utterly irrelevant to real politics outside".
Mr Kennedy said he had reorganised parts of the party since the election.
"You can't as a leader make an omelette without cracking eggs and then you get some unfavourable remarks," he added.
Ms Calton won Cheadle from the Conservatives in 2001 with a majority of 33, the smallest in the country.
Although unable to campaign because of a recurrence of her cancer, Ms Calton increased her majority in this year's May election to 4,000.
Mr Hunter told BBC News he believed there was a "backlash" against the "American-style" canvassing tactics which parties like the Conservatives had used.
"This has been a hard fought campaign. The Conservatives have failed again and have disgraced themselves with more negative and personal mud-slinging than ever before," Mr Hunter said.
He said he was "extremely proud" to be representing Cheadle as their next MP.
Mr Day, who was the area's MP until 2001, said he would not stand as a parliamentary candidate again, adding: "I am pleased to see that the Conservative share of the vote has gone up.
"This is the best by-election result we have had in a long time and it is the Labour Party which is in trouble."
But Labour's Mr Miller said the result "showed that people were willing to vote for anyone to make sure the Conservative Party did not win".
The Conservatives have not gained a seat in a parliamentary by-election since 1982.
Shadow Commons leader Chris Grayling said he was disappointed but not surprised the Tories had failed to win the seat.
He said the result was similar to the general election and little had happened politically since then to "change the overall lie of the land between the different parties".